CONTROLLED DRUG RELEASE FOR POORLY WATER SOLUBLE DRUGS- A ROLE OF POLYMERIC NANOPARTICLES

In the treatment of health related dysfunctions, it is desirable that the drug reaches its site of action at a particular concentration and that this therapeutic dose range remains constant over a sufficiently long period of time to alter the process. Delivery of hydrophobic molecules and proteins has been an issue to poor bioavailability following administration. Thus, micelle carrier systems are being investigated to improve drug solubility and stability. Due to problems with toxicity and immunogenicity, biodegradable polymers are being explored as substitutes for synthetic polymers in the development of new micelle system. By grafting hydrophobic moieties to the biodegradable polymer backbone, self-assembled micelles can be readily formed in aqueous solution. The mechanisms involved in controlled release require polymers with a variety of physicochemical properties. Thus several polymers have been tested as potential drug delivery systems, including nano- and micro-particles, dendrimers, nano- and micro- spheres, capsosomes and micelles. In all these systems, drugs can be encapsulated or conjugated in polymer matrices. This review will provide an overview of the biodegradable polymeric micelles that have been developed for controlled delivery of poorly soluble drugs.