In vitro Biotransformation studies play a crucial role in drug discovery program that determine the fate of the new chemical entities (NCE’s). Enzyme rich matrices such as microsomes, hepatocytes, liver fractions and S9 fractions transform the new chemical entities to different metabolites. Metabolites could be pharmacologically important or toxic. Newly formed metabolites are identified using liquid chromatography interfaced with mass spectrometry. Identification of the biotransformation sites in the new chemical entity helps the medicinal chemists to optimize its structure and develop the NCE as a pharmaceutical drug. Screening pharmaceutical drugs using in vitro biotransformation studies assist in selecting the right new chemical entity for further in vivo studies in animal systems and later in human clinical trials.
Part of the book: Drug Discovery
Androstenedione (AD) is a steroid intermediate valuable for the production of steroid medicaments. Microbial biotransformation of phytosterol to produce AD is a well-researched area. However, low substrate solubility of phytosterol in aqueous media and nucleus degradation of AD to androstadienedione (ADD) or 9-hydroxy-AD are the major obstacles for AD production leading to detailed research for optimization of biotransformation process. In this review, microbial transformation of AD with respect to the existing methods of chemical or biochemical synthesis of AD are extensively discussed. This review examines the microbial biotransformation process and limitations for enhanced AD production. Factors affecting the effective biotransformation process to obtain AD are discussed and limitations are highlighted. The main content of this review focuses on the recent and futuristic biotechnological advances and strategies in techniques to enhance AD bioprocess.
Part of the book: Secondary Metabolites
Screening for novel producer strains and enhanced therapeutic production at reduced cost has been the focus of most of the biopharmaceutical industries. The obligation to carry out prolonged intensive pilot scale experiments gave birth to micro-scale bioreactor systems. Screening large number of microorganisms using shake flasks and benchtop bioreactors is tedious and consumes resources. Microbioreactors that mimic benchtop bioreactors are capable not only of high throughput screening of producer strains, but also aid in optimizing the growth kinetics and expression of proteins. Modern technology has enabled the collection of precise online data for variables such as optical density (OD), pH, temperature, dissolved oxygen (DO), and adjusting in mixing inside microreactors. Microbioreactors have become an irreplaceable tool for biochemical engineers and biotechnologists to perform a large number of experiments simultaneously. Another aspect that is vital to any industry is the product yield and subsequent downstream processing. Perfusion bioreactors are one of the upcoming advances in bioreactor systems that have the potential to revolutionize biologics production. This chapter intends to take a review of different aspects of microbioreactors and perfusion bioreactors including their potential in high throughput pilot studies and microbial and mammalian cell cultivation technologies.
Part of the book: Biotechnology and Bioengineering