Drugs including analgesics need a delivery system to deliver it to the site of action upon administration. Delivery can be achieved using various types of dosage forms including tablets, capsules, creams, ointments, liquids, aerosols, injections, and suppositories. Conventional drug delivery systems provide immediate release of the analgesics without controlling the rate of release. A number of doses must be given daily in order to achieve and maintain effective plasma concentrations. Frequent administration causes fluctuations in plasma levels of the drug. The drug plasma levels could fall below the minimum effective concentration and can also exceed the minimum toxic concentration. The purposes behind controlling the drug delivery for analgesic are to achieve more effective therapies while eliminating the potential for both under and overdosing. The need for fewer administrations for “no pain” maintenance and with optimal use of the drug in question is to avoid adverse effect, and to increased patient compliance. Modified‐release analgesics have enabled patients to better maintain pain control by convenient dosing intervals and sustained blood concentrations. The differences between available modified‐release products are half‐life, cost, and formulation and drug‐release properties.
Part of the book: Pain Relief