The Purpose of designing sustained or controlled delivery systems has always been to bring down the dose frequency that offers better patient compliance & reduced side effects Microspheres have shown to reduce the dose, side effects, frequency of administration and possibility of dose dumping, therefore increased patient compliance. There are several methods of preparation for microspheres, slight variation in basic method can produce numerous changes in final outcome. However various problems are still not resolved with these methods like wide size distribution & poor repeatability. Biodegradation rate of the microspheres in controlled by the composition of the microspheres and consecutively affects the release profile of drug, i.e. PGA, PLA and PCL have hydrolytic degradation role in order of PGA>PLA>>PCL.
Keywords: controlled delivery, microspheres, patient compliance