Microspheres are solid spherical particles ranging in size from 1-1000μm. They are spherical free flowing particles
consisting of proteins or synthetic polymers, which are biodegradable in nature. There are two types of microspheres;
microcapsules and micrometrics, which are described as, Microcapsules are those in which entrapped substance is distinctly
surrounded by distinct capsule wall and in micrometrics entrapped substance is dispersing throughout the microspheres
matrix. Solid biodegradable microspheres incorporating a drug dispersed or dissolved through particle matrix have the
potential for the controlled release of drug. They are made up of polymeric, waxy, or other protective materials, that is,
biodegradable synthetic polymers and modified natural products.It is the reliable means to deliver the drug to the target site
with specificity, if modified, and to maintain the desired concentration at the site of interest without untoward effects.
Microspheres received much attention not only for prolonged release, but also for targeting of anticancer drugs to the
tumour.
Key words: Microspheres, controlled release, micro-particulates, therapeutic efficacy, novel drug delivery
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