ROLE OF NATURAL POLYMERS IN SUSTAINED RELEASE DRUG DELIVERY SYSTEM: APPLICATIONS AND RECENT APPROACHES

Abstract

In recent years there have been important developments in different dosage forms for existing and newly designed drugs and natural products, and semi-synthetic as well as synthetic excipients often need to be used for a variety of purposes. Gums and mucilages are widely used natural materials for conventional and novel dosage forms. These natural materials have advantages over synthetic ones since they are chemically inert, nontoxic, less expensive, biodegradable and widely available. They can also be modified in different ways to obtain tailor-made materials for drug delivery systems and thus can compete with the available synthetic excipients. Various polymers have been investigated as drug retarding agents, each presenting a different approach to the matrix system. Based on the features of the retarding polymer, hydrophilic polymers are the most suitable for retarding drug release and there is growing interest in using these polymers in sustained drug delivery. This review discusses some of the most important plant-derived polymeric compounds that are used or investigated as release retardant in sustained or controlled release drug delivery systems.