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Abstract

Microspheres are small spherical free-flowing particles, with diameters 1 μm to 1000 μm consisting of proteins or synthetic polymers which are biodegradable in nature. They are prepared to obtain prolonged or controlled drug delivery to improve, bioavailability, stability and to target the drug to a specific site at a predetermined rate. Microspheres are of various types and are prepared by different techniques as spray drying technique, solvent evaporation technique, single-emulsion technique, double-emulsion technique, etc. Microspheres do not receive much attention not only for prolonged-release but also for targeting of anticancer drugs. Microspheres can be applied in different fields as in cosmetics, oral drug delivery, target drug delivery, ophthalmic drug delivery, gene delivery, and others discussed in the review. In the future, with various other techniques microspheres will find a place in novel drug delivery, specifically in diseased cell sorting, diagnostics, genetic materials, safe, targeted & effective in-vivo delivery. The present review highlights various types of microspheres, different methods of preparation, its applications, and recent advances in microspherical drug delivery systems.