Formulation and optimization of sustained release Stavudine microspheres using response surface methodology.

The aim of the current study was to formulate and optimize the formulation on the basis of in vitro performance of microsphere. A 3(2) full factorial design was employed to study the effect of independent variables, polymer-to-drug ratio (X(1)) and stirring speed (X(2)), on dependent variables, encapsulation efficiency, particle size, and time to 80% drug release. The best batch exhibited a high entrapment efficiency of 70% and mean particle size 290 μm. The drug release was also sustained for more than 12 hours. The study helped in finding the optimum formulation with excellent sustained drug release.