In order to achieve controlled release of drug and their targeting sites, many approaches have been investigated. Synthetic and naturally occurring absorbable polymers in the form of matrix (monolith) devices, hydrogels, microspheres, nanoparticles, films, and sponges are finding increasing use in drug delivery systems. They hold the promise of providing better drug efficacy, reducing toxicity, and improving patient compliance. The desirable characteristics of polymer systems used for drug delivery, whether natural or synthetic are minimal effect on biological systems after introduction into the body; in vivo degradation at a well-defined rate to nontoxic and readily excreted degradation products; absence of toxic endogenous impurities or residual chemicals used in their preparation. Natural polymers remain attractive primarily because they are natural products of living organisms, readily available, relatively inexpensive, and capable of a multitude of chemical modifications. The present review suggests the naturally available polymers and their application in the controlled release of drugs.
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