Open access peer-reviewed chapter

Solid Lipid Based Nano-particulate Formulations in Drug Targeting

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Bibhash Chandra Mohanta, Subas Chandra Dinda, Narahari Narayan Palei and Jyotirmoy Deb

Submitted: September 13th, 2018 Reviewed: June 27th, 2019 Published: December 3rd, 2019

DOI: 10.5772/intechopen.88268

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Recently, targeted drug delivery systems have gained much more interest for delivering varieties of drugs as well as imaging agents specifically to the targeted disease cells or tissues. These are well known for their increased precision and accuracy in mode of drug delivery along with reduced side effects. Though numerous carriers are being employed for drug targeting, the solid lipid based nanoparticles (SLNs) are preferred over them owing to their ability to encapsulate wide varieties of drugs, biocompatibility, ease of surface modification, scaling up feasibility, and possibilities of both active as well as passive targeting to various organs. Surface of these drug loaded SLNs can be modified by conjugating different ligands to enhance their tissue/organ targeting ability and therapeutic efficacy to much higher extent. In this chapter, we have discussed about the SLNs and their different surface modified forms for passive as well as active targeting to different organ such as (colon, breast, lungs, liver, kidney, brain, eyes, etc.) in combating different diseases.


  • SLNs
  • targeted drug delivery
  • imaging
  • colon
  • breast
  • eye
  • lungs
  • liver
  • kidney
  • brain

1. Introduction

Drug delivery refers to the approaches or methods or technologies of administering or transporting active pharmaceutical ingredient(s) and other xenobiotics through different routes for achieving the desired therapeutic effect in human or animal safely. The pharmacokinetics and pharmacodynamics issues of drugs are the most important considerations of drug delivery which is profoundly integrated with dosage form and route of administration. The kinetics of drug release, drug concentration profile in the plasma, onset of action, duration of action, site of action, and side effects of a drug deeply influenced by the DDS.


2. Conventional vs. targeted drug delivery systems

2.1 Conventional drug delivery systems

Conventional drug delivery system is also known as classical drug delivery system or traditional drug delivery system, which sometimes unable to maintain the steady-state plasma concentration as desired for a specific time period and may not be able to deliver the drugs to the specific site of organ or tissues may be because of barriers in transportation for which it may be needed to administer with multiple doses at a regular time interval or need to go for targeted drug delivery systems.

2.2 Targeted drug delivery systems

Targeted drug delivery system (TDDS) is popularly known as smart drug delivery system. The aim of the TDDS is to localize, target and to have a protected interaction of a drug with the diseased cells/tissues of interest for a prolonged period of time. TDDS helps in maintaining the requisite plasma and tissue drug levels in the body and protects the healthy tissues from damage may be some times caused by the drugs [1]. It offers various benefits over conventional DDS such as localization of a drug to the desired or specific site, enhancement of therapeutic efficacy, reduction in the dosing frequency and toxic side effects, controlled biodistribution of drug, modulated pharmacokinetics, and improved patient compliances [2]. The TDDS is a highly integrated DDS which needs the coordinated effort from various experts such as biologist, chemist, engineers for its fabrication and optimization.

2.3 Nanotechnology vs. drug delivery systems

Nanotechnology is defined as the technology which allows studying, controlling, manipulating and manufacturing of structures or devices in the nanoscale. It is a multi-disciplinary scientific field applying engineering and manufacturing principles at the molecular level. These nanosized objects/structures/devices, e.g. “nanoparticles” exhibit unique properties and function that distinctly differ from those seen from the items made up from the same materials. Nanomaterials possess many unique characteristics such as mechanical, optical, magnetic, electrical, and biochemical, which provoke them to intermingle with complex cellular functions in an exceptional manner [3].

Since its introduction in 1959, the nanotechnology brought a great revolution in all areas of sciences and particularly in drug formulation and drug delivery system design. Nanomedicine is the medical application of nanotechnology, which plays an imperative role in the medical biology, diagnosis, monitoring, prevention and treatment of diseases. Since last few decades, owing to the rapid developments in nanotechnology and carrier materials, a great advancement in the nanoparticulate DDS has been noticed and they are taking the lead among all types of DDS [4].

The nanoparticulate DDS possesses numerous advantages such as higher intracellular uptake (cells and tissues have a greater affinity and acceptability to the nanoparticles as compared to micro/macro molecules), ability to penetrate into sub-mucosal layer (nanometric size), greater suitability for administration through the systemic circulation (nanometric size), greater feasibility/flexibility to develop into a targeted DDS for targeting various sites/organs. Thus, the nanometric size, tailored surface, and cross functionality of these nanoparticles will continue to explore many unexplored research areas and may help in designing and developing new biomedical applications [5].

2.4 Colloidal drug carrier and solid lipid nanoparticles

The term “colloid” is applied to the dispersed system where the dispersed phase particles size are very fine and generally below 1 μm. Thus, the biphasic drug carrier containing very fine dispersed phase particles (<1 μm) which sequester, transport and retain the active drug en route, while they deliver the drug within or in the vicinity of a target is popularly known as colloidal drug carrier. These colloidal drug carriers comprise nanoparticles, liposome, niosome, nanospheres, multiple emulsion, and nanosuspensions, etc. [6]. Colloidal carriers aid in solubilization of lipophilic drug, protect the sensitive drug from degradation in biological fluid, reduce toxic side effect, improve patient compliances, prolong the duration of action and drug targeting potentiality [7].

Though the polymeric nanoparticulate DDS have shown hugely impressive performance for providing therapeutic benefits in the case of long term delivery of a therapeutic agent, but still, the number of polymeric nanoparticulate formulations in the market is still limited. This is because of polymeric toxicity, high cost of polymers, and lack of feasibility for scaling up. Lipid based nanoparticulate DDSs are proposed as an alternative to polymeric nanoparticulate DDS and gained tremendous attention in the field of nanomedicine. These comprise liposomes, niosomes, nanoemulsions, solid lipid nanoparticles (SLNs) and nanostructured lipid carrier (NLCs), etc. [5].

SLNs are the second generation lipid nanocarriers that overcome most of the limitations associated with conventional drug delivery system and other colloidal lipid/polymeric nano carriers. It promises to offer numerous benefits including biocompatibility and biodegradability, physiochemical stability, lower toxicity, ability to incorporate both hydrophilic and lipophilic drugs, improved bioavailability, enhanced in vitroand in vivostability of drugs, controlled-release characteristics, site specificity in drug delivery as well as feasibility in pilot scale up along with its suitability in drug delivery through different routes of administration [4].

2.5 Solid lipid nanoparticles and drug targeting

In the emerging field of nanomedicine, SLNs is at the forefront. It is made up from biocompatible/physiological lipids (e.g. partial glycerides, triglycerides, fatty acids, wax, and steroids) that remain in solid form at room temperature. Numerous techniques are being developed for the fabrication of SLNs using the biocompatible/physiological lipid which has records of innocuous use in medicine [8]. Apart from drugs, the essential materials for fabricating SLNs are solid lipids as matrix materials, emulsifiers, stabilizers, and water. The nanometric size and larger surface area of SLNs is suitable to be embedded with some potential functionalized ligands, antibodies, moieties, and other functional groups that help in drug targeting [5].

The real success of lipid nanoparticles relies on the development of dosage forms that are able to improve the therapeutic index of the drugs by mounting their concentration specifically at the targeted site or organs. Drugs can be incorporated in SLNs which lead to offer a new model in drug delivery that could be applied for drug targeting. The therapeutic payload of various categories of drugs (such as anti-infective, anticancer drugs, anti-inflammatory, etc.), antigens, proteins, and nucleotides can be enhanced in specific site and organs by associating with SLNs. On another side, SLNs face numerous challenges which include rapid clearance, serum instability (dependent on the specific formulation) and nonspecific uptake by the mononuclear phagocytic system (play a major role for opsonizing the foreign particles and remove SLNs from the circulation) [9]. The above mentioned limitations can be nullified by conjugating different ligands to the surface of SLNs which could help to increase the circulation time and targeted delivery of the drug to the specific site. The targeting properties to a specific site can be further enhanced by selecting surface markers [10]. Thus, in this article, we focused on SLNs and various ligand conjugated SLNs which act as suitable carriers for targeting to different sites such as lungs, brain, liver, breast, eyes, colon, kidney, etc.


3. Solid lipid nanoparticles for lungs targeting

Targeted delivery of a drug to the lungs is gaining much more interest at the present time, for the treatment of lungs cancer, tuberculosis, and other airborne diseases where lungs are the primary site of action or site administration of drugs [11]. In order to get maximum therapeutic benefits from lungs delivery, a suitable DDS with appropriate physicochemical properties are necessary and SLN along with ligand conjugated SLN are the most fitted on this ground.

3.1 Solid lipid nanoparticles for active lungs targeting

The lungs offer a very high surface area for rapid absorption of drugs owing to high vascularization and avoidance of the first pass effect. Sometimes, targeted delivery of certain drugs to the lungs is very important not only for improving the bioavailability and therapeutic activity but also for reducing the systemic side effects [5].

To achieve a prolonged hypoglycemic effect, Liu et al. developed insulin-loaded nebulized SLNs which were administered through intrapulmonary route. The hypoglycemic effects, stability of SLN during nebulization, and deposition pattern of the drug were evaluated. SLNs exhibited excellent protective effect for insulin against degradation or leakage from nanospheres and were relatively stable during nebulization viajet nebulizer. Nebulized insulin SLNs helped in improving the bioavailability and showed significantly higher hypoglycemic effect as compared to insulin phosphate buffer solution administered through pulmonary route. Thus nebulized insulin-SLNs could be a promising DDS for the treatment of diabetes [12]. In another study Bi et al. successfully developed freeze dried insulin-SLNs suitable for intra-tracheal administration through a spray. High preservation of insulin was noticed in SLNs after spray freeze drying. They had performed in vivostudies on diabetic rat and observed a prolonged hypoglycemic effect [13].

Rifampicin (RIF) were successfully encapsulated into the SLNs that delivered RIF specifically to the alveolar macrophage (AM) with strong antimycobacterial efficacy (MIC reduced to 1/8 fold than that of the free drug). Generally, mycobacterium safely multiplies in the AM (acts as an incubator), as the mycobacterium is resistant to the biocidal mechanism of AM. The developed SLNs were more stable and the particle sizes were very much suitable for improving RIF’s uptake by AMs which are particle size dependent [14]. Similarly, Rifabutin loaded SLNs significantly improved uptake of the drug by the macrophages which were demonstrated in an in vitromodel [15].

Co-administration of RIF and isoniazid through SLN formulation significantly reduced (60%) degradation of RIF (from 48.81 to 12.35%) from acidic gastric pH owing to the presence of isoniazid. The developed SLNs promoted targeted delivery of drug to the brain with enhanced bioavailability and lesser side effect that could be helpful in the case of cerebral tuberculosis [16].

Significantly higher biodistribution of dexamethasone acetate (DXM) to the lungs was achieved through intravenous administration of DXM loaded SLNs. The area under curve (AUC) of DXM- SLNs was increased by 17.8-fold as compared to DXM-solution. The maximum concentration of the DXM in the lungs was observed at 0.5 h post DXM-SLNs injection [17].

Similarly higher biodistribution of amikacin (AMK) in the lungs was achieved by pulmonary administration of AMK-SLNs as compared to the free drug administered through i.v., which could be helpful in the treatment of cystic fibrosis [18].

3.2 Ligand conjugated solid lipid nanoparticles for passive lungs targeting

Lungs targeted delivery of drugs is a challenging task due to the mucociliary clearance. In this regard, the ligand-anchored DDS not only proves its potential in achieving improved site-specific drug delivery, but also it reduces the chances of drug uptake by reticulo-endothelial system (RES). It is believed to play a major role in congenital defense and exhibit diversified biological activities such as antimicrobial, anticancer, immunomodulation, an exertion to control cell growth, binding, and inhibition of numerous biologically active compounds. However, clinical success of such approaches relies on the choice of appropriate ligand free from immunogenic potential with the potential to provoke cargo internalization by the target cell [19].

The mechanism of receptor mediated endocytosis of ligand anchored SLNs and drug release technique has been shown in Figure 1.

Figure 1.

Mechanism of receptor mediated endocytosis of ligand anchored SLNs and drug release technique.

3.2.1 Lactoferrin (Lf) conjugated solid lipid nanoparticles

In lung associated diseases, receptors of Lactoferrin (80-kDa iron-binding glycoprotein) is overexpressed in the lungs. Thus, Lf conjugated DDS may become a promising tool for targeted delivery of drugs to lungs in lung-associated diseases [20]. Rifampicin (RIF) loaded SLNs were successfully prepared and were coupled with Lf via carbodiimide chemistry i.e., coupling of the Lf carboxylic group with the stearylamine amine group present on the surface of the previously formed RIF loaded SLNs in the presence of N-ethyl-N-(dimethylaminopropyl)-carbodiimide (EDC). An in vivobiodistribution study revealed 3.05 time higher drug uptakes by the lungs in case of Lf-RIF-SLNs as compared to unconjugated RIF-SLNs. It was further confirmed from fluorescence photomicrographs that clearly showed access of the Lf-coupled SLNs into the lung. Thus, lactoferrin is an efficient molecule that can be used for targeting active agents directly to the lungs [21].

3.2.2 Wheat germ agglutinin (WGA) conjugated solid lipid nanoparticles

Conjugation of bioadhesive ligand molecules with SLNs helps in improving drug absorption/bioavailability by increasing residence time in the GIT and reducing dosing frequency. Lectins (a group of diverse proteins/glycoproteins) are the bioadhesive ligand and have stable structure and receptor binding ability. It offers resistance to enzymatic digestion/degradation, which helps in its in vivosurvival for a prolonged time period [22]. Wheat germ agglutinin (WGA) is an example of nontoxic plant lectin which binds particularly to N-acetyl-D-glucosamine and sialic acid on cell surfaces. Conjugation of WGA with SLNs could be helpful for targeted delivery of antitubercular drugs to the lungs.

WGA conjugated SLNs loaded with rifampicin (WRSLNs) were successfully developed for lungs specific delivery of rifampicin (RIF). The conjugation of WGA to RIF loaded SLN was carried out by two-steps carbodiimide reaction reported by Ertl et al. with slight modification [23]. Even after conjugation with the SLNs, the WGA retained its bio-recognition activity and sugar-binding specificity [24]. From the in vivostudy result, the interaction of WRSLNs with porcine mucin was confirmed. However, non-conjugated SLNs did not show any conjugation with the porcine mucin. The WRSLNs were stable at refrigerated temperature and also in presence of electrolytes up to 1.0 M Na2SO4 concentration. The WRSLNs were 10 times more stable than RIF-SLN which could be owing to the steric stabilization by lectin present on nanoparticle surface. Prepared WRSLNs had shown narrow size distribution, controlled release of a drug, retention of biorecognition activity and improved physical stability of drug against electrolyte induced flocculation [25].

3.2.3 Mannose conjugated solid lipid nanoparticles

Studies on tuberculosis revealed overexpression of the mannose receptors specifically on alveolar macrophages (AM) surfaces [26]. Keeping it in mind attempts were taken to develop mannosylated SLN to deliver antitubercular drugs targeting to alveolar macrophages which have higher affinity for mannose. Rifabutin loaded mannosylated SLNs were successfully developed. Manosylation was done by ring opening reactions followed by reaction of aldehyde groups of mannose in 0.1 M sodium acetate buffer (pH 4.0) with the amino groups of lipid. This leads to formation of Schiff’s base (–N=CH–), which may then get reduced to secondary amine (–NH–CH2–) and remain in equilibrium with Schiff’s base at basic pH. In vivostudies were conducted to evaluate for their cytotoxicity, targeting potential, AM uptake, and hematological studies. It was reported that mannosylation improved uptake (up to 6-fold) of rifabutin by the AM. Moreover, mannosylated rifabutin-SLNs were less immunogenic and helped in sustained delivery of drug. Thus, the mannosylated SLNs may be employed for AM targeted delivery of rifabutin for effective management of TB [27].

Overexpression of mannose receptors in case of lungs cancer was reported by numerous investigators. The mannosylated-distearoyl phosphatidyl-ethanolamine SLNs loaded with paclitaxel (PTX) was developed for lungs targeted delivery of PTX. Manosylation was done by ring opening reaction followed by reaction of an aldehyde group of mannose with the free amine group provided by stearylamine and DSPE in sodium acetate buffer (pH 4.0). The stability testing data indicated that SLNs formulations stored at 4 ± 2°C were more stable than those stored at 27 ± 2°C. It was revealed that mannosylated SLNs deliver significantly higher concentration of drug to the alveolar cell sites and showed improved antiproliferative efficacy as compared to PTX solution and PTX-SLNs [28].

3.2.4 Folate conjugated solid lipid nanoparticles

The folate receptors (α- form) are overexpressed on the surface of lung tumor cells. The extents of the overexpression are different in different types of lung tumors (adenocarcinomas—72%, squamous cell carcinomas—51%, small cell carcinoma—25%, and lung metastases—30%) [29]. These receptors allow folate derivatives to bind preferentially that permits intracellular incorporation of folate derivative by endocytosis.

Folate-conjugated copolymer of polyethylene glycol (PEG) and N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC) SLNs loaded with Paclitaxel (PTX) were successfully developed. The conjugation of folate- conjugated PEG and HTCC to RIF-SLN was carried out by carbodiimide mediated coupling chemistry. Pulmonary administration of the developed F-PEG-HTCC–SLNs selectively delivered the PTX to the lung’s cancer cells with improved penetrability and prolonged lung residence. Moreover, the developed SLN significantly reduced the in vitrohalf-maximum inhibitory concentration of PTX in M109-HiFR cells [30].

List of SLNs and their different ligand conjugated forms for lungs targeting have been summarized in Table 1.

Sl. noSLN (Type)LipidsPreparation methodDrugsTargetModelCommentsRef.
01SLNSA, PAReverse micelle-double emulsionInsulinLungsMale SD ratsImproved hypoglycemic effect[12]
02SLNSA, PAModified lipid film hydration methodRIFAMSD ratsImproved drug uptake by AMs.[14]
03SLNSL, GTSUltrasonication with high pressure homogenizationDXMLungsMiceImproved therapeutic efficacy targeting to lungs[17]
04Lf-SLNsSLSolvent injection methodRIFLfRAlbino ratsTargeted delivery of RIF to Lungs[21]
05WGA-SLNSA, GMSSingle emulsification followed by solvent evaporationRIFMucinPorcineControlled release of RIF[25]
06Msy-SLNTSNModified solvent injection methodRFBMRJ774 & albino ratsAM specific drug delivery. Enhanced therapeutic efficacy.[27]
07Msy-SLNTSN, DSPEModified solvent injection methodPTXMRA549 & Male albino ratAlveolar cell site delivery of drug with enhanced anti-proliferative efficacy.[28]
08Ft-SLNCHO, GSNano precipitation methodPTXFRHeLa & M109- HiFR cellsProlonged drug residence time, reduced MIC[30]

Table 1.

List of SLNs and their different ligand conjugated forms for lungs cells targeting.


4. Solid lipid nanoparticles for brain targeting

Targeted delivery of drugs to the brain for is gaining much more interest at the present time, not only for the treatment of brain tumor and other neurodegenerative disorders but also for their diagnosis. Brain targeted delivery of drugs is the most challenging task because of the presence of strongest physiological barrier, i.e., blood brain barrier (BBB). It is a highly selective semipermeable membrane barrier constituted by specialized microvascular endothelial cells, basement membrane and glial cells (astrocytes, neurons, and pericytes). As long as the BBB remains integral, the drugs remain ineffective in the brain. Though BBB is a major issue for it, yet it offers scores of opportunities such as presence of numerous transport proteins and specialized receptors [5].

Conventional approach for the treatment of brain tumor and other brain-related disorders needs a higher dose of the drug that leads to systemic toxicity and substantial adverse effects on CNS and vital normal tissues. However, various researchers have reported SLNs to be a suitable DDS targeting the brain as the SLNs possess numerous unique characteristics, such as improved uptake of SLN by the brain due to lipidic nature, bioacceptability and biodegradability nature, non-toxic, nano sized particles suitable for prolonged circulation time in blood scale up feasibility, absence of burst drug release effect [31]. Thus, SLN could be used as potential as well as promising candidate for brain targeting.

4.1 Solid lipid nanoparticles for active brain targeting

SLNs are the most acceptable brain targeted DDS employed in brain tumor owing to their ability to escape and/or inhibit P-glycoprotein in the blood–brain barrier [32]. Camptothecin (CMP) loaded SLN were successfully developed for the treatment of glioma. Encapsulation of drug in phospholipids and conjugation with the peptide enhances the permeation of drug across BBB, which leads to brain targeted delivery of the drug. The developed SLN was stable in terms of size and charge within a year of storage which might be due to appropriated acidic pH (inclusion of behenic acid into the lipid core of the SLNs). DMPC (1,2-dimyristoyl-sn-glycero-3-phospho-choline) membrane helps in efficient release of the incorporated CMP into the brain parenchyma crossing the BBB. Against glioma, the developed SLNs showed higher cell death or antitumor activity using the lowest maximal inhibitory concentration (IC50) values. Biodistribution study revealed higher accumulation of CMP in the brain in the case of SLNs as compared to other non-encapsulated drugs. However, pharmacokinetics study revealed lower deposition of CMP in peripheral organs indicating lesser toxicological effects in the vital organ. Thus, in short, the SLNs exhibited enhanced accumulation, distribution, and retention of camptothecin in the animal brain along with superior in vitroantitumor activity against glioma [33].

Riluzole (RLZ), a potent neuroprotective agent is useful in the treatment of neurodegeneration including traumatic brain injury and amyotrophic lateral sclerosis. RLZ-SLNs were able to deliver the riluzole successfully to the brain which helps in preventing acute cell damage induced by glutamate in neurodegenerative diseases of motor neurons. Moreover, it also protects dopamine neuron in the case of Parkinson’s disease. Stability studies on RLZ-SLNs were also carried out at pH 1.1, 5.5 and 7.4, and in human plasma which revealed the absence of riluzole degradation in all the investigated media [34].

Vinpocetine (VIN), a derivative of vincamine alkaloid, useful against chronic cerebral vascular ischemia. VIN loaded SLN were successfully developed and achieved the objectives of delivering the drugs to the brain. Release kinetics of the developed SLN followed zero-order sustained release profile [35].

4.2 Ligand conjugated solid lipid nanoparticles for passive brain targeting

4.2.1 Lactoferrin conjugated solid lipid nanoparticles

Augmentation of drug uptake into the brain is a subtle mission in the treatment of brain tumor. Lactoferrin (Lf) receptor present on the BBB in different species along with the cell surface of glioblastomas [36]. Keeping it in mind, various researchers tried to target lactoferrin receptor through conjugation of lactoferrin with SLNs for active targeting to brain tumor. Moreover, this conjugated system showed higher stability, and drug payload.

Lactoferrin (Lf) conjugated SLNs loaded with docetaxel (DTX) were able to show effective brain targeting efficiency. Carbodiimide chemistry was employed for conjugation of Lf on SLN surface (Lf-SLN). Receptor saturation studies and distribution studies of lipidic nanoparticles in the brain indicated brain targeting mechanism for uptake in brain tumor cell and brain respectively. The Lf-SLNs were more stable. It not only showed significantly higher DTX concentration in the brain but also showed superior apoptotic activity when compared with unconjugated SLNs and DTX. Thus it was confirmed that conjugation of Lf to SLN significantly improved the targeting potential of the DTX for brain tumor [37].

4.2.2 Tamoxifen-Lactoferrin cross conjugated solid lipid nanoparticles

P-glycoprotein (P-gp) and multidrug resistance-associated proteins (MRAPs) are localized on brain microvascular endothelial cells (BMEC) which pump out the substances/drug out from the central nervous system. Tamoxifen (Tf), a selective estrogen receptor modulator possibly reverse the capability of efflux transporters like MRAPs in cancer cells [38]. Thus, incorporation of Tf could help in preventing a wide range of medication from efflux loss. Lactoferrin (Lf) receptors are overexpressed in BMEC and glioblastoma multiforme (GBM) cells. It is reported that the Lf cause inhibition to the multiplication of malignant GBM cells.

Tamoxifen (Tx) and lactoferrin (Lf) cross-conjugated carmustine (CRM)-loaded SLNs were developed. For conjugation of Tx on CRM-SLN, the carbonyl groups of the SLN were first activated with 0.1% (w/v) carbodiimide and 0.05% (w/v) N-hydroxysuccinimide. The suspended SLNs were then crosslinked with 0.05%, 0.1%, 0.15%, or 0.2% (w/v) Tx at 150 rpm and 25°C for 3 h and centrifuged. Further Lf conjugation was done by reacting Lf (0.02%, 0.04%, 0.06%, or 0.08%) (w/v) with the activated CRM-SLNs and Tx-CRM-SLN. The conjugated SLNs were more stable which could be due to inclusion of behenic acid into the lipid core. These were efficiently penetrated through a monolayer of human BMEC and human astrocytes and to target GBM cells. A 10-fold increase in the permeability of BBB and improved the sustained release of CRM was achieved with the help of the developed SLNs as compared to unconjugated CRM-SLNs. Thus, TX and Lf cross-conjugated SLNs enhance the BBB permeability of the drug with improved anti-proliferative action against GBM [39].

4.2.3 PEG conjugated solid lipid nanoparticles for gene delivery

Treatment of brain tumor through siRNA is preferable, as it can target specifically to one gene and is able to silence it in a post-transcriptional way. Moreover, siRNA can target several functional proteins available at the BBB [40]. Treatment of brain tumor through siRNA, needs a safe, stable, effective carrier which must be able to cross the BBB. The SLNs are mostly preferred as it meets most of the criteria which siRNA needs. Targeted delivery of gene by SLNs is a bi-stage system. Conjugation of angiopep to SLN surface for targeting the low-density lipoprotein receptor-related protein-1(expressed in BBB) is the initial step. The proteolytic cleavage of PEGylated lipopeptide, which releases PEG, glutamic acid residues and release of siRNA for high silencing efficiency is the second stage [5].

siRNA encapsulated SLNs were successfully developed using a combination of titrable cationic lipids. For effective gene delivery, it was PEGylated after incorporating MMP-cleavable lipopeptide. The in vitrostudy indicated that the developed SLNs showed higher uptake and gene knockdown efficacy. SLNs also showed low cytotoxicity which was owing to masking of intrinsic positive charge of SLNs by PEGylated cleavable lipopeptide. In in vivostudies, angiopep functionalization played a vital role as a mediator of transport across the BBB and targeting to glioma [41].

4.2.4 Apolipoprotein E conjugated solid lipid nanoparticles

Low density lipoprotein (LDL) receptors are overexpressed on the BBB and apolipoprotein E (AP-E), a plasmatic protein is easily recognized by these receptors. Resveratrol (RSV), polyphenolic flavonoid promises to offer neuroprotective effects which are helpful in neurological disorders like Alzheimer’s, Parkinson’s, Huntington’s diseases, brain ischemia, and epilepsy. The AP-E conjugated resveratrol (RSV) SLNs were successfully developed. The binding of ApoE to the SLNs surface was carried out by spontaneous interaction between the previously biotinylated ApoE and the covalently attached avidin on the SLNs surface, resulting in two different ApoE-functionalized SLNs: SLN-DSPE-ApoE and SLN-Palmitate-ApoE. These conjugated SLNs were sufficiently stable and were able to prevail over the issues of RSV like low solubility, degradation but also to help its brain targeted delivery. Brain targeted delivery of RSV by such SLNs follows a bi-stage system. The AP-E-RSV-SLNs mimic lipoprotein particles that are endocytosed into the BBB endothelium via the LDL receptor and then transcytosed to the brain [42].

List of SLNs and their different ligand conjugated forms for brain cell targeting have been summarized in Table 2.

Sl. noSLN (Type)Lipid (s)Preparation methodDrugsTargetModelCommentsRef.
01SLNCP, DMPCHigh shear homogenization and ultrasonication techniquesCMPBrainHuman glioma & Monocytic cell line. Wistar ratsEnhanced accumulation of CMP. Superior in vitroantitumor activity[33]
02SLNCOMP, SPCWarm oil-in-water microemulsion techniqueRLZBrainMale SD ratsHigher bioaccumulation of RLZ in brain.[34]
03SLNSA, GMS, PRE, GTPHigh shear homogenization and ultrasonication techniquesVINBrainZero-order sustained drug release kinetics[35]
04Lf-SLNGMS, SA, SLEmulsification and solvent evaporation methodDTXLf ReceptorsU-87 MG cell lines & Swiss albino miceImproved the brain targeting potential[37]
05Tf-Lf-SLNsTPM, DSPEHomogenization followed by centrifugationCRMTf and Lf ReceptorsU87MG, HBMECsHigher BBB permeability. Superior anti-proliferative action[39]
06SLNPOPC, DSPE, CHO, DMDetergent dialysis techniquesiRNAAngiopepbEnd.3 cell, U87MG cells,Higher uptake and gene knockdown efficacy[41]
07AP-E -SLNsCPHigh shear homogenization followed by sonication techniqueRSVLDL ReceptorhCMEC/D3 Cell lineBrain targeted delivery of RSV[42]

Table 2.

List of SLNs and their different ligand conjugated forms for brain cell targeting.


5. Solid lipid nanoparticles for liver targeting

Though targeted delivery of a drug to the liver is a challenging task, still, it is an interesting approach in the treatment of various liver disorders. In the treatment of liver disorders, drugs targeting to the liver, face irresistible obstacles from various physiological barriers and processes like uptake by the reticuloendothelial system, mechanical entrapment by the pulmonary vascular bed, and opsonization process [43].

Numerous approaches are being proposed to enhance bioaccumulation/biodistribution of drugs to liver and hepatocytes. These approaches include both active targeting as well as passive accumulations of nanoparticulate formulation due to ligand (carbohydrate, peptide, antibodies conjugation) conjugated nanoparticles. Recently, liver targeted deliveries of drugs by the SLNs are gaining much attention in the treatment of various types of liver disorders. Thus, various liver targeting strategies using SLNs are enlightened below.

5.1 Solid lipid nanoparticles for active targeting

Baicalin (BCL), a natural product obtained from Scutellaria baicalensis(Family: Labiatae) popularly used in the treatment of Hepatitis-B and liver fibrosis. BCL loaded SLNs were developed. The prepared SLNs were stable and were able to enhance the therapeutic efficacy of BCL by improving its biodistribution in the liver. In vivobiodistribution, targeting evaluation and in vitroanti-oxidant study reveals that the developed BCL-SLNs have substantial liver targeting, improved anti oxidative and hydroxyl radical scavenging abilities [44].

Ficus benjamina(Family: Moraceae) is rich in phenolic (chlorogenic, p-coumaric, ferulic and syringic acids) and total flavonoid content that are effective against chronic alcoholism induced fatal liver and cardio-renal injury. Ethanolic extract of Ficus benjamina(FB) loaded in SLNs (FBSLNs) helped in bioaccumulation of the phenolic and flavonoid content in the liver due to lipophilic nature of SLNs. In vivoevaluation of FBSLNs against hepatic and cardio-renal injury revealed its hepatoprotective activity which was further evident from various biological parameters and histopathological photomicrography. In the liver, accumulation of aldehyde level was reduced that validated the detoxifying nature of FBSLN. Moreover, restoration of aberrant cardio-renal biomarkers and histological consequences revealed the cardio-renal protective potential of FBSLNs [45].

Berberine (BBR), an active constituent of Coptis chinensis(Family: Ranunculaceae) have potential pharmacological effects on type-2 diabetes. It has already been validated that BBR enhances glucose and lipid metabolism through the activation of adenosine monophosphate-activated protein kinase (AMPK) and improve insulin sensitivity. BBR loaded SLNs (BBR-SLNs) were developed to improve the beneficial effect of BBR on hepatosteatosis. The effect of BBR-SLNs on lipid metabolism were studied which revealed gaining of body weight and reduction in liver weight with simultaneous reduction of serum alanine transaminase and liver triglyceride level. Biodistribution study reported 20-fold increase in the concentration of drug in the liver than that of blood. Moreover, it reduced the accumulation of fat and lipid droplet size. It was also noticed that the expression of lipogenic genes was down-regulated and lipolytic gene was up-regulated in BBR-SLNs treated livers which could be helpful in the treatment of hepatosteatosis [46].

Cisplatin (CSPT) is an anti-cancer drug which is used in the treatment of many malignancies including hepatocellular carcinoma, lungs carcinoma, etc. The CSPT loaded SLNs (CSPT-SLNs) were successfully developed and were stable in terms of drug content after storage for 3 months in different temperature and humid conditions. In vivotissue distribution study revealed that the developed CSPT-SLNs were able to deliver a higher amount of CSPT particularly to the liver as compared to the brain, lungs, and kidney [47].

Sorafenib (SFB), a potent multi-kinase inhibitor possess anti-tumor angiogenesis effect (block vascular endothelial growth factor (VEGF) and platelet-derived growth factor receptor (PDGFR)) and is preferentially used in the treatment of hepatocellular carcinoma. The SFB loaded SLNs (SFB-SLNs) were developed with an objective of improving bioavailability and reducing adverse effects. The results of the stability test showed that SRF-SLNs remained stable for more than 1 month at room temperature. In vivostudy of SFB-SLNs revealed improved bioavailability (increased by 66.7%) with remarkably higher bioaccumulation of drug in the liver (2.20-fold higher drug selectivity index value) when compared with the SFB suspension [48].

Primaquine phosphate (PP) is an antimalarial drug that acts on the primary tissue forms of the Plasmodium which after growth within the liver, initiate the erythrocytic stage. Thus, PP loaded SLNs (PP-SLNs) were developed with an aim to deliver liver schizonticide PP directly to the hepatocytes. Stability of the PP-SLNs in suspension was tested for a period of 3 months in terms of size, poly-dispersity, ζ-potential, and pH. There were no noteworthy changes in size, poly-dispersity, ζ-potential, or pH occurred over time. In vivostudy report revealed that the developed SLNs were highly effective (>20%) against hypnozoites/liver stage of all malarial species with a reduced dose when compared with the conventional oral dose [49].

5.2 Solid lipid nanoparticles delivering gene

The fibrous scars occurring in the liver due to the increased production and deposition of hepatic extracellular matrix (ECM) components are called liver fibrosis reduce the physiological performance of the liver. Hepatitis viral infection is one of the major reasons for liver fibrosis and cirrhosis. Administration of antifibrotic therapeutics (e.g. connective tissue growth factor (siRNA) responsible for the cellular and molecular basis of fibrogenesis) is one of the most preferable approaches for the treatment of liver fibrosis. The siRNA loaded cationic SLNs (cSLNs) were developed by gently mixing CSLNs with siRNA at various weight ratios of cSLN to siRNA in 0.1 M PBS (pH 7.4) and then incubated at room temperature for 15 min. Naturally obtained low-density lipids (LDLs) were used in the preparation. The developed cSLN were able to silence the targeted gene in the presence of serum with notably low cytotoxicity. The cSLNs were PEGylated which were hydrodynamically stable and were able to protect their siRNA cargo from nuclease degradation during systemic circulation. The developed cSLNs loaded with siRNA administer through intravenous route delivered siRNA exclusively to the liver and resulted in a considerable reduction in collagen content and pro-fibrogenic factors with spectacular progress of pathophysiological symptoms in a liver fibrosis rat model. Biodistribution study revealed site-specific delivery and accumulation of siRNA loaded cSLNs to the liver tissues [50].

5.3 Solid lipid nanoparticles for passive targeting

5.3.1 Polyethylene glycol conjugated (PEGylated) solid lipid nanoparticles for passive targeting

PEGylated SLNs are reported to be preferentially accumulated in the liver as the kidney is unable to clear the same. Thus, in liver disorders, liver targeting strategy using PEGylation technique is used for delivering numerous drugs. Paclitaxel (PTX) loaded PEGylated SLNs were successfully developed for targeting the liver, in the case of hepatic carcinoma. The cellular uptake study revealed that PTX loaded PEGylated SLNs showed prolonged circulation time in plasma and higher bioaccumulation of drug in the liver when compared with the PTX solution [51].

The preferential drug targeting ability of PEGylated SLNs to cancer cells have been shown in Figure 2.

Figure 2.

PEGylated SLN in targeting preferentially to cancer cells.

5.3.2 Galactosylated lipid [N-hexadecyl lactobionamide] conjugated solid lipid nanoparticles

The parenchymal cells of the liver contain asialoglycoprotein receptors which recognize terminal b-D-galactose or N-acetylgalactosamine residues. The N-hexadecyl lactobionamide (N-HLBA) was synthesized via an amide bond between the amine group of hexadecylamine and the carboxyl group of lactobionic acid. The lactobionic acid was converted to 1,5-lactone that contain more reactive amine groups. Cucurbitacin B (CurB), a tetracyclic triterpene shows significant pharmacological activities including anti-tumor, anti-hepatitis, hepatocurative and hepatoprotective. The CurB loaded N-hexadecyl lactobionamide (N-HLBA) conjugated SLNs were developed for liver-targeted delivery of CurB. The N-HLBA SLN with anchored galactose moiety via amide bonds might achieve effective liver-targeting delivery in vivoby retaining the surface galactose in blood stream, and by exposing a higher amount of galactose to the liver parenchymal cells. The optimum zeta potential held up the physical stability whereas the optimum particle size distribution offered the convenience for intravenous administration and deep penetration into targeting area. The Biodistribution study of the CurB loaded N-hexadecyl lactobionamide (N-HLBA) conjugated SLNs revealed a 2.5-fold increase in the amount of CurB in the liver when compared with CurB-SLN. In vitrocytotoxicity study revealed enhancement of cytotoxicity. The experimental result validated the liver targeting ability of N-HLBA conjugated SLNs [52].

List of SLNs and their different ligand conjugated form for liver targeting have been summarized in Table 3.

Sl. noSLN (Type)Lipid(s)Preparation methodDrugsTargetModelCommentsRef.
01SLNSL, GMSEmulsification ultrasonic dispersion methodBCLLiverRatsImproved biodistribution of BCL in Liver, Superior anti oxidative and hydroxyl radical scavenging abilities[44]
02SLNSAHot-homogenization followed by ultra-sonicationFBLiverHepG2 cell line, RatsAnti-oxidant, anti-inflammatory and detoxification potential[45]
03SLNGL, SP, TPHot Emulsification TechniqueBBRLiverMale db/db mice,Down regulate the lipogenic gene and Up-regulate the lipolytic gene.[46]
04SLNSAWarm emulsification followed by sonicationCSPTHepatocellular carcinomasWistar ratsHigher bioaccumulation of drug in liver[47]
05SLNGBHigh-speed shearing followed by ultrasonicationSFBLiverFemale SD RatsImproved bioavailability, higher bioaccumulation in liver[48]
06SLNSAModified multiple emulsion solvent evaporation techniquePPHepatocytes3D7, MiceImproved antimalarial activity[49]
07C-SLNCOModified emulsification and solvent evaporation methodsiRNALDL ReceptorRat, HSCs and hepatocytesSpectacular progress of pathophysiological symptoms in liver fibrosis[50]
08PEG-SLNGT, CHOSolvent-emulsification methodPTXHepatocytesHepG2, MCF7, PANC-1Higher liver bioaccumulation of PTX[51]
09G-SLNCOMPHigh-pressure homogenizationCurBASGP ReceptorWistar ratsEnhanced antitumor and hepatoprotective activity[52]

Table 3.

List of SLNs and their different ligand conjugated forms for liver cell targeting.


6. Solid lipid nanoparticles for breast cell targeting

Breast cancer is the most common form of cancer and the second most deadly disease among the woman around the globe. The breast cancer new incidences and mortality rate has been increased by 20 and 14% since 2008.

Recently, controlled release of the drugs to the targeted site of the disease using a nanocarrier vehicle is getting more attention as it enhances the therapeutic efficacy of the drugs. Solid lipid nanoparticulate (SLN) formulations possess an endless potential to deliver active chemotherapeutic molecules in a programmed prototype to improve bioavailability and nullify the side-effects. The bio-compatibility and bio-degradability characteristics of SLNs promise to offer a lesser toxic product as compared to polymeric nanoparticles which forced to consider it as an idealistic targeted drug delivery system for breast cancer therapy [5].

6.1 Solid lipid nanoparticle for active breast cell targeting

6.1.1 SLNs for photodynamic therapy

Photodynamic therapy is one of the emerging approaches in the treatment of cancer which comprises application of a photosensitizer followed by laser irradiation of tumor lesions. Temoporfin (TP), a photosensitizer loaded in thermoresponsive SLNs were developed with an objective to improve anticancer activity through site specific drug delivery. The copolymer poly(ethylene oxide)-block-poly(ε-caprolactone) copolymers (PEO45-b-PCL7) were synthesized by the mechanism of catalyst-free ring opening polymerization of ε-caprolactone which was initiated by poly(ethylene oxide) monomethyl ether(MPEO). These copolymers were acts as a stabilizer in the preparation of thermoresponsive SLN. The stability study report revealed that the developed SLNs had higher stability in human serum within the blood transport to tumor tissue. In vitrophototoxicity study revealed higher phototoxic activity of TP against breast cancer cells due to its faster bioaccumulation in the targeted cancer cells. The in vivoanticancer efficacy of TP-SLN was remarkably higher as compared to the commercial TP formulation [53].

6.1.2 Manganese (Mn) II complex solid lipid nanoparticles

Transition metal complex (e.g., Manganese II complex [Mn2(μ(C6H5)2CHCOO)2(bipy)4]± 2) has been extensively used for cancer therapy nowadays due to its potential anticancer activity (interact with the DNA). Mn(II) complex loaded SLNs were developed that showed superior cytotoxicity activity on breast cancer cells. The zeta potential value of the product was higher indicating good physical stability and dispersion quality of the SLNs. Cell proliferation assay revealed that the normal cell death rate was lower with Mn(II) SLNs which indicated lesser toxicity of the product to the normal cell. Moreover, higher early apoptosis rate was observed with Mn(II) complex SLN as compared to Mn(II) alone [54].

6.2 Solid lipid nanoparticles for passive breast cell targeting

6.2.1 Fucose conjugated solid lipid nanoparticles

Fucose receptors are overexpressed in the breast cancer cell. Thus, conjugation of fucose to SLNs was proposed to deliver the drug specifically to breast cancerous cells. Fucose conjugated methotrexate (MTX) loaded SLNs were developed to achieve enhanced targeting potential for breast cancer cells. Fucosylation of MTX-SLNs was related with opening of fucose ring and reaction of its aldehyde group with free amino functionalities expressed over the surface of MTX-SLNs in sodium acetate buffer (pH 4.0). The above process led to the formation of Schiff’s base (–N=CH). The Schiff’s base might be reduced to secondary amine (–NHCH2) and establish equilibrium with Schiff’s base. Physical stability of prepared SLNs was higher which could be due to positive zeta potential value that provides repulsive interaction between nanosized lipid particles preventing particle aggregation. The ex vivostudy revealed higher cellular uptake as well as higher cytotoxicity at lower IC50 of MTX. The in vitrostudy results showed increased rate apoptosis with a change in lysosomal membrane permeability and a higher rate of lysosomal membrane degradation. The in vivostudy revealed maximum bioavailability and tumor targeting efficiency with minimum secondary drug distribution to other organs [55].

6.2.2 Folic acid functionalized solid lipid nanoparticles

The folate receptor (FR) is one of the most widely evaluated receptor for active targeting of anticancer therapeutics in the case of in breast cancer cells. Folic acid has many advantages over antibody ligands such as small size, non-immunogenicity, non-toxicity, ease of handling, stability and low cost [56]. Several researchers had reported earlier that the FA functionalized SLNs were able to deliver the chemotherapeutic agent, particularly to the cancerous cells. Thus, FA functionalized SLNs co-encapsulated with Docetaxel (DTX) and Curcumin (CUR) were successfully developed to enhance its therapeutic efficacy against breast cancer cells. FA-stearic acid (FA–SA) conjugate was synthesized by classical 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) chemistry and incorporated in the DTX-CUR-SLN. Additionally, PEG–stearic acid (PEG–SA) was incorporated to obtain FA-DTX-CUR-SLN. The DTX-CUR-SLN and FA-DTX-CUR-SLN formulations were found to be stable at refrigerated condition for 2 months. Both the formulations showed sign of instability at accelerated condition (25°C/65% RH). The developed FA functionalized SLNs exhibited improved pharmacokinetic parameters, superior cancer cell targeting efficiency, and improved therapeutic efficacy of DTX. Folic acid was believed to be responsible for the targeting efficacy of the developed SLNs to the breast cancer cell. This conjugated system showed significant increase in area under the curve and mean residence time of the drug. Co-conjugation (FA and PEG) to SLNs co-encapsulated with DTX and CUR responsible for synergistic activity of both DTX and CUR. Moreover, bioaccumulation of DTX in heart and kidney was found very low which signified avoidance of vital organ toxicity [57].

6.2.3 Cetamide and trimethylphytosphingosine-iodide co-conjugated solid lipid nanoparticles

The sphingosine-1-phosphate (S1P), phytosphingosine, ceramides, and sphingosine are the metabolites of sphingolipids and are reported as essential structural components of cell membranes or important mediators of cellular process that regulate the proliferation, survival, and death of cells. Moreover, sphingosines including N,N,N-trimethylsphingosine (TMP-I) have been reported for their role as a negative modulator of transmembrane signaling through protein kinase C (PKC) as well as an inhibitor of sphingosine kinase-1 (SK-1), controlling the various membrane-associated signaling mechanisms associated with cell growth and inhibitory apoptosis in tumor cells [58]. Ceramide, a kind of sphingosine conjugated with fatty acid residue, is also reported to enhance the sensitivity of MDR-acquired cancer cell lines to chemotherapeutic agents [59]. Thus, attempts were made to employ ceramide (CD) and trimethylphytosphingosine-iodide (TMP-I) as a targeting agent for docetaxel (DTX) loaded SLNs. The prepared SLNs were physically stable without any significant change in their physical appearance, drug content, and particle size over a period of 8 weeks at 4°C. CD enhanced the DTX sensitivity in MDR-acquired cancer cell lines. In vivoclearance of drug and tumor growth inhibitors were significantly decreased in case of CD and TMP-I conjugated SLNs when compared with the marketed product. Thus, CD and TMP-I conjugated DTX-SLN could serve as a potentials alternative parenteral formulations of DTX [60].

List of SLNs and their different ligand conjugated form for breast cancer cell targeting have been summarized in Table 4.

Sl. noSLN (Type)Lipid(s)DrugsPreparation methodTargetModelCommentsRef.
01SLNTDTMPModified hot homogenization and ultrasonication methodBreast Cancer cell4T1, MDA-MB-231, Female Nu/Nu mice- MDA-MB-231Exhibited improved phototoxicity and anticancer efficacy[53]
02Mn (II) Complex-SLNCOMPMn (II) complexHot homogenization methodBreast Cancer cellMCF-7 and HUVEC cell linePossessed superior anticancer activity with reduced toxic effect.[54]
03F-SLNPL90NG, PL, STA, GELMTXHot microemulsion methodFucose ReceptorMCF-7 Cell line & Female SD ratImproved bioavailability and tumor targeting efficiency with minimum secondary drug distribution in various organs.[55]
04FA-PEG-SLNGMS, SACUR, DTXModified ethanol injection methodFolic acid ReceptorMCF-7 &MDA-MB-231Cell line. Female Wistar RatSynergistic cancer efficacy due to coencapsulation of DTX and CRM along with targeted delivery of drugs[57]
05CD-TMP I-SLNPC, TMS,DTXHigh-pressure homogenization methodCD & TMP-1MCF-7 cell, MCF-7/ADR cellsSignificant increased antitumor efficacy with targeted drug delivery[60]

Table 4.

List of SLNs and their different ligand conjugated forms for breast cancer cell targeting.


7. Solid lipid nanoparticles for eye targeting

The eye is one of the delicate organs of human and one of the most delicate routes of drug delivery. However, the eye poses unique challenges relative to drug delivery due to the ocular anatomical and physiological constraints. SLNs are one of the promising targeted DDS for an eye. Numerous drugs such as antibiotics, plasmids, anti-inflammatory, and immunosuppressive agents were encapsulated in SLNs for the treatment of ophthalmic disorders.

7.1 Solid lipid nanoparticles for active eye targeting

Corneal neovascularization (CNV), a sight-threatening condition is caused due to various inflammatory settings including chemical injury. Single-stranded proline-modified short hairpin anti-angiopoietin-like protein 2 (ANGPTL2 RNA) interference molecules acts as potent angiogenic and pro-inflammatory factor and is used for the treatment of CNV [61]. Thus, ANGPTL2 RNA loaded SLNs were developed to deliver the interference molecule specifically to the retina. The single-stranded RNAi (pshRNA) loaded SLNs exhibit high stability in vivoand preliminary data suggest that pshRNA is less susceptible to degeneration due to RNase activity. The fluorescence-labeled developed SLNs eye drops penetrated all layers of cornea and expression of ANGPTL2mRNA was considerably inhibited in both epithelium and stroma. Further, the area of angiogenesis was remarkably decreased in the corneas by the SLNs drops as compared to the control group [62].

X-linked juvenile retinoschisis (XJR), a retinal degenerative disorder caused by mutation in the RS1 gene encoding a retinoschisin [63]. Among non-viral vectors, solid lipid nanoparticles (SLNs) represent one of the most effective lipid-based colloidal carriers, and for gene delivery to the posterior segment of the eye [64]. Plasmid (human RS1 gene) loaded SLNs were developed for the treatment of XJR diseases which showed significant improvement of the retinal structure with photoreceptor specific expression of the RS1 gene [65].

Tobramycin (TMC) is one of the most preferable drugs to treat vitreoretinal diseases, such as bacterial infections, endophthalmitis, cytomegalovirus retinitis (CMV), uveitis, proliferative vitreoretinopathy (PVR), diabetic retinopathy, age-related macular degeneration [66]. Thus TMC loaded mucoadhesive SLNs were developed which showed higher bioaccumulation of drugs in most of the ocular tissues and was able to penetrate into the retina. Moreover, it resulted in enhanced intraphagocytic antibiotic concentration in polymorphonuclear granulocytes and superior bactericidal activity against Pseudomonas aeruginosa. The developed SLNs showed good stability up to 12 months with no aggregation or precipitation phenomena, variations in zeta potential values or in amount of the drug encapsulated into the nanoparticles [67].

7.2 Solid lipid nanoparticles for passive eye targeting

7.2.1 Chitosan coated solid lipid nanoparticles

Indomethacin (IMC), a topical non-steroidal anti-inflammatory drug (NSAID) is used for ocular inflammatory disorders such as conjunctivitis, uveitis, cystoid macular edema, and anterior segment inflammation, including post-operative pain following cataract surgery [68]. Chitosan (Cs) coated IMC loaded SLNs (IMC-Cs-SLN) were developed to deliver NSAID to the posterior segment of ocular tissues and for improving the pre-corneal residence time and transcorneal permeability characteristics. For surface modification of the developed SLNs, the chitosan was incorporated into the aqueous phase prior to preparation of the SLNs. The developed SLNs were stable in terms of drug loading, EE, and less drug expulsion during storage at 40°C for 90 days. The SLNs showed higher bioaccumulation of IMC in the ocular tissues. The IMC-Cs-SLN showed superior trans-membrane IMC permeation characteristics which were due to penetration enhancing properties of Cs [69].

7.2.2 Intercalated montmorillonite solid lipid nanoparticles

Betaxolol hydrochloride (BH) is widely used for the treatment of ocular hypertension and open-angle glaucoma in clinical therapeutics. However, it faces certain limitations like low bioavailability and pre-ocular retention, and some side effects. In order to overcome these limitations acid treated montmorillonite (Mt)- Betaxolol Hydrochloride (BH) nanocomposite encapsulated SLNs (Mt-BH-SLNs) were developed. An acid-treated montmorillonite (acid-Mt) was first intercalated with BH in the interlayers and this nanocomposite was encapsulated by SLNs. The developed Mt-BH-SLNs possess good stability. Long term irritation test reported that the (Mt-BH-SLNs) showed no damage for cornea and conjunctiva. The corneal hydration level of Mt-BH-SLNs was higher (78.25 ± 0.63)% indicating higher drug corneal permeability and absence of irritation to the cornea. Thus, Mt-BH-SLNs could be used for effective management of glaucoma [70].

7.2.3 Polyethylene glycol (PEG) conjugated (PEGylated) solid lipid nanoparticles

Ketoconazole (KTZ) is a broad spectrum antifungal agent, with high lipo-solubility [71] but a short ocular half-life (elimination half-life is 19 min in aqueous humor and 43 min in cornea) [72] and very poor solubility (0.04 mg/ml). Ketoconazole (KTZ) loaded PEGylated SLNs were developed for targeted delivery of KTZ to the posterior part of the eye for treatment of fungal infection. It showed higher bioavailability both in the aqueous and vitreous humor with significant antifungal potential. The ex vivocorneal permeation study revealed higher corneal permeability of the PEGylated KTZ-SLNs. The developed SLN was satisfying various parameters suitable for ocular delivery such as pH, osmolarity, stability, autoclavability, particle size, preservation against contamination. The SLNs were found to be stable in terms of entrapment efficiency and total drug content at 2–8°C for 12 months. Thus it could be helpful in the treatment of keratitis and endophthalmitis [73].

List of SLNs and their different ligand conjugated forms for eye targeting have been summarized in Table 5.

Sl. noSLN (Type)Lipid(s)DrugsPreparation methodTargetModelCommentsRef.
01SLNDSGPC, CHOANGPTL2 RNAHydration method followed by extrusionRetinaC57BL/6 miceInhibition of expression of ANGPTL2mRNA, Reduction in angiogenesis area[62]
02SLNPREHuman RS1 geneSolvent emulsification followed by evaporationRetina661W, RS1h-deficient mouseImprovement of the retinal structure[65]
03SLNSATMCWarm o/w microemulsion methodAqueous humorAlbino rabbitSuperior bactericidal activity[67]
04Cs-SLNGBIMCHot homogenizationPosterior segment of ocular tissueWhite albino RabbitsImproved biodistribution of IMC at posterior segment[69]
05Mt-SLNsPC, GMSBHEmulsion evaporation-low temperature solidification methodCornea and ConjunctivaRabbitSignificantly reduced inflammation, No irritation[70]
06PEG-SLNsCOMPKTZEmulsification followed by high pressure homogenizerUpper posterior eyeARPE-19 & RCE Cell line, RatSuperior antifungal activity[73]
07Multifunctional SLNsCPBAI (Drug) C IR-780 (Diagnostic agent)Modified solvent-diffusion methodColorectal partLoVo, CHO-K1Imaging, Superior cytotoxicity[75]
08SIA-PEGylated SLNGMS, OADXMSolvent diffusion methodE-selectin receptorHUVECs, ICR male MiceTargeted delivery of DXM for ischemia-reperfusion-induced injury-induced AKI[78]

Table 5.

List of SLNs and their different ligand conjugated forms for eye, colon and kidney targeting.


8. Solid lipid nanoparticles for passive colon targeting

Combination of nanocarriers and electroporation techniques is named as electropermeabilization which is commonly used for enhancing drug transport. The Cyanine–type IR 780 and Baicalein (BAI) co-encapsulated SLNs were developed for both imaging and therapy of colorectal carcinoma where cyanine–type IR 780 and baicalein (flavonoid derivative) were acting as a diagnostic agent (photosensitizer) and therapeutic cargo respectively. For preparation of SLNs the organic phase was prepared by dissolving IR-780, BAI, and melted lipid in dichloromethane. The organic phase was then added dropwise to hot aqueous phase containing surfactant under vigorous stirring. Supplementary material (flavonoids) facilitated in the reduction of dose and reduction in normal cell toxicity in cancer chemotherapy. The external electric field pulses applied in electroporation helped in increased of cell membrane permeability, either by generating transient pores or membrane electropermeabilization [74]. Electropermeabilization mediated administration of the developed SLNs showed cytoskeletal abnormalities more significantly then without electropermeabilization. The prepared SLNs particles were with good physical stability. With electroporation support, the developed SLNs showed increased p53 and manganese superoxide dismutase expression with significant higher cytotoxicity, thus validating their suitability for combined therapy and molecular imaging simultaneously [75].

List of SLNs and their different ligand conjugated form for colon targeting have been summarized in Table 5.


9. Solid lipid nanoparticles for kidney targeting

9.1 Solid lipid nanoparticles for passive kidney targeting

9.1.1 Polyethylene glycol (PEG) surface modified solid lipid nanoparticles

Icariin (IRN) is widely used as traditional Chinese medicine for the treatment of kidney diseases and reinforce yang. The PEG surface modified Icariin (IRN) loaded SLNs (PEG-IRN-SLNs) was developed for targeted delivery of IRN to the kidney and to improve the bioavailability. The SLN was prepared by high temperature melt-cool solidification method. Upon comparing with IRN solution it was revealed from the pharmacokinetic study that the biological half-life (t1/2) and area under curve (AUC) of PEG-IRN-SLN was 7-fold and 4-fold higher. Biodistribution study revealed that IRN concentration in kidney tissues was significantly increased. Moreover, the relative target efficiency to kidney tissues was 79% and relative tissue exposure was 16.95. Thus the develop SLN could be helpful in the treatment of kidney diseases [76].

9.1.2 Sialic acid conjugated PEGylated solid lipid nanoparticles

E-selectin is a promising target for the site-specific delivery of anti-inflammatory agents. Several researchers have reported that sialic acid (SA)-mediated micelles could be specifically internalized by lipopolysaccharide (LPS)-activated human umbilical vein endothelial cells (HUVECs) via the specific binding between SA and E-selectin receptor [77]. Sialic acid (SIA) conjugated PEGylated dexamethasone (DXM) loaded SLNs (SIA-PEGylated-DXM-SLN) were developed to deliver DXM specifically to the kidney and to improve the therapeutic efficacy of DXM for renal ischemia–reperfusion injury (IRI)-induced acute renal injury. The Sialic acid (SIA) conjugated PEGylated DXM (SIA-PEG-DXM) was synthesized by adding PEG-DXM, dicyclohexylcarbodiimide (DCC), and 4-dimethylaminopyridine (DMAP) into anhydrous dimethyl formamide (DMF) followed by addition of SIA into the solution. The resulting mixture was stirred for obtaining SIA-PEG-DXM. The crude product was purified by dialysis against deionized water for 2 days, followed by lyophilization. The developed SLNs potentially had good colloidal stability in human body. The study revealed that the apoptotic human umbilical vein endothelial cells (HUVECs) were significantly decreased. It indicated the suitability of SIA-PEGylated-SLNs for internalization by the inflamed vascular endothelial cells. Biodistribution study revealed higher renal accumulation of DXM (range 2.7- to 5.88-fold higher) after 6 h of intravenous administration. The Pharmacodynamic study revealed that higher blood biochemical indexes, histopathological changes, oxidative stress levels, and pro-inflammatory cytokines which indicated improved renal function by the influence of SIA-PEGylated DXM [64].

List of SLNs and their different ligand conjugated form targeting to the kidney have been summarized in Table 5.


10. Conclusion

Though drug targeting to a specific site in the body is an interesting approach, it is a highly challenging task. Despite that a large variety of smart nanocarriers have been developed for drug targeting in recent years, SLN has achieved a special status among them and can be employed for both passive as well as active targeting. These can be employed for delivering not only the drug but also antibody, proteins, genes, imaging agents etc. and bring about increased cellular uptake at the targeted disease sites. Moreover, surface modification of SLNs through conjugation of various ligands on SLNs surfaces helped in enhancing its targeting efficacy in terms of cellular binding, uptake and intracellular transport to different cells as well as organs and ensure its greatest potentiality to combat wide ranges of diseases. However, the intrinsic complexity of biological environments strongly influences its functionality and often complicates their effective use for therapeutic treatments. Therefore, a deeper knowledge and understanding of the real interactions involved in the diseased tissues is fundamental for the development of therapeutic protocols of SLNs.

Conflict of interest

The authors confirm that this article content has no conflicts of interest.

AMalveolar macrophages
ANGPTL2 RNAsingle-stranded proline-modified short hairpin anti-angiopoietin-like protein 2
AP-Eapolipoprotein E
BHbetaxolol hydrochloride
CIR-780cyanine-type IR-780
COcholesterol oleate
COMPcompritol 888 ATO
CPcetyl palmitate
c-SLNcationic SLN
Cs-SLNchitosan coated SLNs
CurBcurcumin B
DSPEG1,2-distearoyl-snglycero-3-phosphoethanolamine-N-[carboxy(polyethylene glycol)-2000]
FA-PEG-SLNfolic acid-polyethylene glycol cross conjugated SLN
FBFicus benjamina
FRfolate receptor
F-SLNfucose conjugated SLN
Ft-SLNfolate conjugated SLN
GBglyceryl behenate
GMSglyceryl monostearate
GSglyceryl stearate
G-SLNsgalactosylated lipid conjugated SLNs
GTglycerol trioleate
GTPglyceryl tripalmitate
GTSGlycerol tristearate
HSChepatic stellate cells
LDLlow density lipid
LfRlactoferrin receptor
Lf-SLNlactoferrin SLN
MICminimum inhibitory concentration
Mn (II) complex[Mn2(l (C6H5)2CHCOO)2(bipy)4](bipy)(ClO4)2 complex
MRmannose receptor
Msy-SLNmannosylated SLN
Mt.intercalated montmorillonite SLN
PApalmitic acid
PL90NGPhospholipon 90NG
PPprimaquine phosphate
PREPrecirol ATO5
SAstearic acid
SLsoya lecithin
SIAsialic acid
siRNAsmall interfering RNA
SPsoybean phospholipid
SPCsoya phosphatidylcholine
STAstearyl amine
WGA-SLNwheat germ agglutinin conjugated SLN
3D7asexual intraerythrocytic stage of P. falciparum laboratory strain (3D7)


  1. 1. Himri I, Guaadaoui A. Cell and organ drug targeting: Types of drug delivery systems and advanced targeting strategies. In: Grumezescu AM, editor. Nanostructures for the Engineering of Cells, Tissues and Organs: From Design to Applications. Oxford, United Kingdom: Willium Andrew Applied Science Publisher (an imprint of Elsevier); 2018. pp. 1-66. DOI: 10.1016/B978-0-12-813665-2.00001-6
  2. 2. Saltzman WM, Torchilin VP. Drug delivery systems. In: Access Science. 16th ed. Chicago: McGraw-Hill Education; 2016. DOI: 10.1036/1097-8542.757275
  3. 3. Singh R, Willard JJW. Nanoparticle-based targeted drug delivery. Experimental and Molecular Pathology. 2009;86:215-223. DOI: 10.1016/j.yexmp.2008.12.004
  4. 4. Bibhas CM, Subas CD, Gitanjali M, Narahari NP. Exploring the use of lipid based nano-formulations for the management of tuberculosis. Journal of Nanosciences: Current Research. 2017;2(3):1-15. DOI: 10.4172/2572-0813.1000112
  5. 5. Palei NP, Mohanta BC, Sabapathi ML, Das MK. Lipid-based nanoparticles for cancer diagnosis and therapy. In: Grumezescu AM, editor. Organic Materials as Smart Nanocarriers for Drug Delivery. Oxford, United Kingdom: Willium Andrew Applied Science Publisher (an imprint of Elsevier); 2018. pp. 415-470. DOI: 10.1016/B978-0-12-813663-8.00010-5
  6. 6. Sharma J, Kalra S, Sharma A, Rani S. Colloidal drug carriers. The Internet Journal of Family Practice. 2009;9(2):1-6
  7. 7. Maiti S, Sen KK. Drug delivery concepts. In: Maiti S, Sen KK, editors. Advanced Technology for Delivering Therapeutics. Rijeka, Croatia: IntechOpen; 2016. pp. 1-13. DOI: 10.5772/65245
  8. 8. Rostami E, Kashanian S, Azandaryani AH, Faramarzi H, Dolatabadi JEN, Omidfar K. Drug targeting using solid lipid nanoparticles. Chemistry and Physics of Lipids. 2014;181:56-61. DOI: 10.1016/j.chemphyslip.2014.03.006
  9. 9. Deshpande A, Mohamed M, Daftardar SM, Patel M, Boddu SHS, Nesamony J. Solid lipid nanoparticles in drug delivery: Opportunities and challenges. In: Mitra A, Cholkar K, Mandal A, editors. Emerging Nanotechnologies for Diagnostics, Drug Delivery and Medical Devices Micro and Nano Technologies. Amsterdam, Netherlands: Elsevier; 2017. pp. 291-330. DOI: 10.1016/B978-0-323-42978-8.00012-7
  10. 10. Dhanasekaran S, Chopra S. Getting a handle on smart drug delivery systems—A comprehensive view of therapeutic targeting strategies. In: Sezer AD, editor. Smart Drug Delivery System. Rijeka, Croatia: IntechOpen; 2015. pp. 31-62. DOI: 10.5772/61388
  11. 11. Mansour HM, Rhee YS, Wu X. Nanomedicine in pulmonary delivery. International Journal of Nanomedicine. 2009;4:299-319. DOI: 10.2147/IJN.S4937
  12. 12. Liu J, Gong T, Fu H, et al. Solid lipid nanoparticles for pulmonary delivery of insulin. International Journal of Pharmaceutics. 2008;356(1–2):333-344. DOI: 10.1016/j.ijpharm.2008.01.008
  13. 13. Bi R, Shao W, Wang Q, Zhang N. Solid lipid nanoparticles as insulin inhalation carriers for enhanced pulmonary delivery. Journal of Biomedical Nanotechnology. 2009;5:84-92. DOI: 10.1166/jbn.2009.036
  14. 14. Chuan J, Li Y, Yang L, Sun X, Zhang Q, Gong T, et al. Enhanced rifampicin delivery to alveolar macrophages by solid lipid nanoparticles. Journal of Nanoparticle Research. 2013;15:1634-1641
  15. 15. Gospar DP, Faria V, Goncalves LMD, Taboada P, Remuñán-López C, Almeida AJ. Rifabutin-loaded solid lipid nanoparticles for inhaled antitubercular therapy: Physicochemical and in vitro studies. International Journal of Pharmaceutics. 2016;497:199-209
  16. 16. Singh H, Bhandari R, Kaur IP. Encapsulation of rifampicin in a solid lipid nanoparticulate system to limit its degradation and interaction with isoniazid at acidic pH. International Journal of Pharmaceutics. 2013;446:106-111
  17. 17. Xiang QY, Wang MT, Chen F, Gong T, Jian YL, Zhang ZR, et al. Lung-targeting delivery of dexamethasone acetate loaded solid lipid nanoparticles. Archives of Pharmacal Research. 2007;30(4):519-525
  18. 18. Varshosaz S, Ghaffari SF, Mirshojaei A, Jafarian F, Atyabi F, Kobarfard SA. Biodistribution of amikacin solid lipid nanoparticles after pulmonary delivery. BioMed Research International. 2013;2013:1-8. DOI: 10.1155/2013/136859
  19. 19. Muro S. Challenges in design and characterization of ligand-targeted drug delivery systems. Journal of Controlled Release. 2012;164(2):125-137. DOI: 10.1016/j.jconrel.2012.05.052
  20. 20. Elfinger M, Maucksch C, Rudolph C. Characterization of lactoferrin as a targeting ligand for nonviral gene delivery to airway epithelial cells. Biomaterials. 2007;28:3448-3455. DOI: 10.1016/j.biomaterials.2007.04.011
  21. 21. Shilpi S, Vimal VD, Soni V. Assessment of lactoferrin-conjugated solid lipid nanoparticles for efficient targeting to the lung. Progress in Biomaterials. 2015;4:55-63. DOI: 10.1007/s40204-015-0037-z
  22. 22. Gorelik E, Galili U, Raz A. On the role of cell surface carbohydrates and their binding proteins (lectins) in tumor metastasis. Cancer Metastasis Reviews. 2001;20:245-277. DOI: 10.1023/A:101553542759
  23. 23. Ertl B, Franziska H, Wirth M, et al. Lectin-mediated bioadhesion: Preparation, stability and Caco-2 binding of wheat germ agglutinin-functionalized poly(D,L-lactide-co-glycolic acid)-microspheres. Journal of Drug Targeting. 2000;8:173-184. DOI: 10.3109/10611860008996863
  24. 24. Coelho LCBB, Silva PMDS, Lima VLDM, Pontual EV, Paiva PMG, Napoleão TH, et al. Lectins, interconnecting proteins with biotechnological/pharmacological and therapeutic applications. Evidence-based Complementary and Alternative Medicine. 2017;2017:1-22. DOI: 10.1155/2017/1594074
  25. 25. Pooja D, Tunki L, Kulhari H, Reddy BB, Sistla R. Characterization, biorecognitive activity and stability of WGA grafted lipid nanostructures for the controlled delivery of Rifampicin. Chemistry and Physics of Lipids. 2015;193:11-17. DOI: 10.1016/j.chemphyslip.2015.09.008
  26. 26. Lane KB, Egan B, Vick S, Abdolrasulnia R, Shepherd VL. Characterization of a rat alveolar macrophage cell line that expresses a functional mannose receptor. Journal of Leukocyte Biology. 1998;64(3):345-350. DOI: 10.1002/jlb.64.3.345
  27. 27. Nimje N, Agarwal A, Saraogi GK, Lariya N, Rai G, Agrawal H, et al. Mannosylated nanoparticulate carriers of rifabutin for alveolar targeting. Journal of Drug Targeting. 2009;17(10):777-787. DOI: 10.3109/10611860903115308
  28. 28. Sahu PK, Mishra DK, Jain N, Rajoriya V, Jain AK. Mannosylated solid lipid nanoparticles for lung-targeted delivery of paclitaxel. Drug Development and Industrial Pharmacy. 2015;41(4):640-649. DOI: 10.3109/03639045.2014.891130
  29. 29. Shi H, Guo J, Li C, Wang Z. A current review of folate receptor alpha as a potential tumor target in non-small-cell lung cancer. Drug Design, Development and Therapy. 2015;9:4989-4996. DOI: 10.2147/DDDT.S90670
  30. 30. Rosière R, Van Woensel M, Gelbcke M, Mathieu V, et al. New folate-grafted chitosan derivative to improve delivery of paclitaxel-loaded solid lipid nanoparticles for lung tumor therapy by inhalation. Molecular Pharmaceutics. 2018;15(3):899-910. DOI: 10.1021/acs.molpharmaceut.7b00846
  31. 31. Brioschi AM, Calderoni S, Zara GP, Priano L, Gasco MR, Mauro A. Solid lipid nanoparticles for brain tumors therapy: State of the art and novel challenges. In: Sharma HS, editor. Progress in Brain Research. Amsterdam, Netherlands: Elsevier; 2009. pp. 193-223. DOI: 10.1016/S0079-6123(08)80011-8
  32. 32. Kuo YC, Liang CT. Inhibition of human brain malignant glioblastoma cells using carmustine-loaded catanionic solid lipid nanoparticles with surface antiepithelial growth factor receptor. Biomaterials. 2011;32:3340-3350
  33. 33. Martins SM, Sarmento B, Nunes C, et al. Brain targeting effect of camptothecin-loaded solid lipid nanoparticles in rat after intravenous administration. European Journal of Pharmaceutics and Biopharmaceutics. 2013;85:488-502. DOI: 10.1016/j.ejpb.2013.08.011
  34. 34. Bondì ML, Craparo EF, Giammona G, Drago F. Brain-targeted solid lipid nanoparticles containing riluzole: Preparation, characterization and biodistribution. Nanomedicine. 2010;5(1):25-32. DOI: 10.2217/nnm.09.67
  35. 35. Morsi NM, Ghorab DM, Badie HA. Brain targeted solid lipid nanoparticles for brain ischemia: Preparation and in vitro characterization. Pharmaceutical Development and Technology. 2013;18(3):736-744. DOI: 10.3109/10837450.2012.734513
  36. 36. Fillebeen C, Descamps L, Dehouck MP, Fenart L, Benaı̈ssa M, Spik G, et al. Receptor-mediated transcytosis of lactoferrin through the blood-brain barrier. The Journal of Biological Chemistry. 1999;274:7011-7017. DOI: 10.1074/jbc.274.11.7011
  37. 37. Singh I, Swami R, Pooja D, et al. Lactoferrin bioconjugated solid lipid nanoparticles: A new drug delivery system for potential brain targeting. Journal of Drug Targeting. 2016;24(3):212-223. DOI: 10.3109/1061186X.2015.1068320
  38. 38. Lee WL, Cheng MH, Chao HT, Wang PH. The role of selective estrogen receptor modulators on breast cancer: From tamoxifen to raloxifene. Taiwanese Journal of Obstetrics & Gynecology. 2008;47(1):24-31. DOI: 10.1016/S1028-4559(08)60051-0
  39. 39. Kuo YC, Cheng SJ. Brain targeted delivery of carmustine using solid lipid nanoparticles modified with tamoxifen and lactoferrin for antitumor proliferation. International Journal of Pharmaceutics. 2016;499:10-19. DOI: 10.1016/j.ijpharm.2015.12.054
  40. 40. Gomes MJ, Martins S, Sarmento B. siRNA as a tool to improve the treatment of brain diseases: Mechanism, targets and delivery. Ageing Research Reviews. 2015;21:43-54. DOI: 10.1016/j.arr.2015.03.001
  41. 41. Brunn J, Larsen TB, Jolck RI, et al. Investigation of enzyme-sensitive lipid nanoparticles for delivery of siRNA to blood–brain barrier. International Journal of Nanomedicine. 2015;10:5995-6008. DOI: 10.2147/IJN.S87334
  42. 42. Neves AR, Queiroz JF, Reis S. Brain-targeted delivery of resveratrol using solid lipid nanoparticles functionalized with apolipoprotein E. Journal of Nanbiotechnology. 2016;14(27):1-11. DOI: 10.1186/s12951-016-0177-x
  43. 43. Mishra N, Yadav NP, Rai VK, Sinha P, Yadav KS, Jain S, et al. Efficient hepatic delivery of drugs: Novel strategies and their significance. BioMed Research International. 2013;2013:1-20. DOI: 10.1155/2013/382184
  44. 44. Yang P, Lian YU, Yan-qiu HU, Li-na MA, et al. Study on targeting andin vitroanti-oxidation of baicalin solid lipid nanoparticles. Chinese Herbal Medicines. 2012;4(4):335-339. DOI: 10.3969/j.issn.1674-6348.2012.04.012
  45. 45. Sharma AK, Kumar A, Kumar S, Mukherjee S, et al. Preparation and therapeutic evolution of Ficus benjamina solid lipid nanoparticles against alcohol abuse/antabuse induced hepatotoxicity and cardio-renal injury. RSC Advances. 2017;7:35938-359490. DOI: 10.1039/C7RA04866A
  46. 46. Xue M, Zhang L, Yang M-X, Zhang W. Berberine-loaded solid lipid nanoparticles are concentrated in the liver and ameliorate hepatosteatosis in db/db mice. International Journal of Nanomedicine. 2015;10:5049-5057. DOI: 10.2147/IJN.S84565
  47. 47. Doijad RC, Manvi FV, Godhwani DM, Joseph R, Deshmukh NV. Formulation and targeting efficiency of cisplatin engineered solid lipid nanoparticles. Indian Journal of Pharmaceutical Sciences. 2008;70(2):203-207. DOI: 10.4103/0250-474X.41456
  48. 48. Wang H, Wang H, Yang W, et al. Improved Oral bioavailability and liver targeting of sorafenib solid lipid nanoparticles in rats. AAPS PharmSciTech. 2018;19(2):761-768. DOI: 10.1208/s12249-017-0901-3
  49. 49. Owuor JJ, Oloo F, Ouma D, Omwoyo WN, et al. Optimization and characterization of primaquine-loaded solid lipid nanoparticles (SLN) for liver schizonticide targeting by freeze drying. MOJ Drug Design Development & Therapy. 2017;1(3):104-112
  50. 50. Kong WH, Park K, Lee MY, et al. Cationic solid lipid nanoparticles derived from apolipoprotein-free LDLs for target specific systemic treatment of liver fibrosis. Biomaterials. 2013;34:542-551. DOI: 10.1016/j.biomaterials.2012.09.067
  51. 51. Bani-Jaber A, Cui H, Elsaid A, Yalcin M, Sudha T, Mousa SA. Pegylated solid lipid nanoparticles reconstituted from high-density lipoprotein components for hepatic targeting. Science Letters Journal. 2015;4:145
  52. 52. Wang W, Zhao X, Hu H, Chen D, Gu J, Deng Y, et al. Galactosylated solid lipid nanoparticles with cucurbitacin B improves the liver targetability. Drug Delivery. 2010;17(3):114-122
  53. 53. Brezaniova I, Hruby M, Kralova J, Kral V, et al. Temoporfin-loaded 1-tetradecanol-based thermoresponsive solid lipid nanoparticles for photodynamic therapy. Journal of Controlled Release. 2016;241:34-44
  54. 54. Guney EG, Cecener G, Dikmen G, Kani I, Egeli U, Tunca B. A novel [Mn2(μ-(C6H5)2CHCOO)2(bipy)4](bipy)(ClO4)2 complex loaded solid lipid nanoparticles: Synthesis, characterization and in vitro cytotoxicity on MCF-7 breast cancer cells. Journal of Microencapsulation. 2016;33(6):575-584. DOI: 10.1080/02652048.2016.1228704
  55. 55. Garg NK, Singh B, Jain A, et al. Fucose decorated solid-lipid nanocarriers mediate efficient delivery of methotrexate in breast cancer therapeutics. Colloids and Surfaces. B, Biointerfaces. 2016;146:114-126
  56. 56. Li W Jr, Szoka FC. Lipid-based nanoparticles for nucleic acid delivery. Pharmaceutical Research. 2007;24:438-449. DOI: 10.1007/s11095-006-9180-5
  57. 57. Pawar H, Surapaneni SK, Tikoo K, Singh C, et al. Folic acid functionalized long-circulating co-encapsulated docetaxel and curcumin solid lipid nanoparticles: In vitro evaluation, pharmacokinetic and biodistribution in rats. Drug Delivery. 2016;23(4):1453-1468
  58. 58. Petremand J, Widmann C. Lipid metabolism: Sphingolipids- from membrane constituents to signaling molecules that control cell-to-cell communications. Current Opinion in Lipidology. 2008;19(6):620-621
  59. 59. Devalapally H, Duan Z, Seiden MV, Amiji MM. Modulation of drug resistance in ovarian adenocarcinoma by enhancing intracellular ceramide using tamoxifen-loaded biodegradable polymeric nanoparticles. Clinical Cancer Research. 2008;14(10):3193-3203
  60. 60. Balakrishnan P, Song CK, Jahu A, Cho HJ. Ceramide and N,N,N trimethyl phytosphingosine-iodide (TMP-I)-based lipid nanoparticles for Cancer therapy. Pharmaceutical Research. 2016;33:206-216
  61. 61. Kanda A, Noda K, Oike Y, Ishida S. Angiopoietin-like protein 2 mediates endotoxin-induced acute inflammation in the eye. Laboratory Investigation. 2012;92:1553-1563. DOI: 10.1038/labinvest.2012.111
  62. 62. Taketani Y, Usui T, Toyono T, et al. Topical use of angiopoietin-like protein 2 RNAi-loaded lipid nanoparticles suppresses corneal neovascularization. Molecular Therapy--Nucleic Acids. 2016;5:e292. DOI: 10.1038/mtna.2016.1
  63. 63. Sikkink SK, Biswas S, Parry NR, Stanga PE, Trump D. X-linked retinoschisis: An update. Journal of Medical Genetics. 2007;44:225-232. DOI: 10.1136/jmg.2006.047340
  64. 64. Rodríguez-Gascón A, Solinís MA, dei Pozo-Rodríguez A, Delgado D, Pedraz JL. Lipid nanoparticles for gene therapy. Patent No. US 20120183589 A1; 2012
  65. 65. Apaolaza PS, Rodríguez AP, Solinís MA, et al. Structural recovery of the retina in a retinoschisin-deficient mouse after gene replacement therapy by solid lipid nanoparticles. Biomaterials. 2016;90:40-49. DOI: 10.1016/j.biomaterials.2016.03.004
  66. 66. Novack GD, Robin AL. Ocular pharmacology. Journal of Clinical Pharmacology. 2016;56:517-527. DOI: 10.1002/jcph.634
  67. 67. Chetonia P, Burgalassia S, Monti D, et al. Solid lipid nanoparticles as promising tool for intraocular tobramycin delivery: Pharmacokinetic studies on rabbits. European Journal of Pharmaceutics and Biopharmaceutics. 2016;109:214-223. DOI: 10.1016/j.ejpb.2016.10.006
  68. 68. Toker MI, Erdem H, Erdogan H, Arici MK, Topalkara A, Arslan OS, et al. The effects of topical ketorolac and indomethacin on measles conjunctivitis: Randomized controlled trial. American Journal of Ophthalmology. 2006;141(5):902-905. DOI: 10.1016/j.ajo.2005.12.004
  69. 69. Balguri SP, Adelli GR, Majumdar S. Topical ophthalmic formulations of indomethacin for delivery to the posterior segment ocular tissues. European Journal of Pharmaceutics and Biopharmaceutics. 2016;109:224-235. DOI: 10.1016/j.ejpb.2016.10.015
  70. 70. Hou D, Hu S, Huang Y, et al. Preparation and in vitro study of lipid nanoparticles encapsulating drug loaded montmorillonite for ocular delivery. Applied Clay Science. 2016;119(2):277-283. DOI: 10.1016/j.clay.2015.10.028
  71. 71. Logua AD, Faddabs AM, Anchisib C, Maccionib AM, Sinicob C, Schivoa ML, et al. Effects of in-vitro activity of miconazole and ketoconazole in phospholipid formulations. The Journal of Antimicrobial Chemotherapy. 1997;40:889-893. DOI: 10.1093/jac/40.6.889
  72. 72. Zhang J, Wang L, Gao C, Zhang L, Xia H. Ocular pharmacokinetics of topically-applied ketoconazole solution containing hydroxypropyl beta-cyclodextrin to rabbits. Journal of Ocular Pharmacology and Therapeutics. 2008;24:501-506
  73. 73. Kakkar S, Karuppayil SM, Raut JS, et al. Lipid-polyethylene glycol based nano-ocular formulation of ketoconazole. International Journal of Pharmaceutics. 2015;495(1):276-289. DOI: 10.1016/j.ijpharm.2015.08.088
  74. 74. Kotulska M. Electrochemotherapy in cancer treatment. Advances in Clinical and Experimental Medicine. 2007;16(5):601-607
  75. 75. Kulbacka J, Pucek A, Kotulsk M, et al. Electroporation and lipid nanoparticles with cyanine IR-780 and flavonoids as efficient vectors to enhanced drug delivery in colon cancer. Bioelectrochemistry. 2016;110:19-31
  76. 76. Liu K-p, Wang L-f, Li Y, Yang B, Du C, Wang Y. Preparation, Pharmacokinetics, and tissue distribution properties of icariin-loaded stealth solid lipid nanoparticles in mice. Chinese Herbal Medicines. 2012;4(2):170-174. DOI: 10.3969/j.issn.1674-6384.2012.02.012
  77. 77. Hu JB, Kang XQ, Liang J. E-selectin-targeted sialic acid-PEGdexamethasone micelles for enhanced anti-inflammatory efficacy for acute kidney injury. Theranostics. 2017;7:2204-2219. DOI: 10.7150/thno.19571
  78. 78. Hu JB, Song G-L, Liu D, et al. Sialic acid-modified solid lipid nanoparticles as vascular endothelium-targeting carriers for ischemia-reperfusion-induced acute renal injury. Drug Delivery. 2017;24(1):1856-1867. DOI: 10.1080/10717544.2017.1410258

Written By

Bibhash Chandra Mohanta, Subas Chandra Dinda, Narahari Narayan Palei and Jyotirmoy Deb

Submitted: September 13th, 2018 Reviewed: June 27th, 2019 Published: December 3rd, 2019