Formulation and Evaluation of Controlled Release Floating Microballoons of Stavudine.

The aim of this study was to formulate and evaluate stavudine floating microballoons for controlled drug release. Initially, the drug-loaded low-density granular pellets were prepared with hydroxypropyl methylcellulose E5 grade and by using isopropyl alcohol as a granulating fluid. Further, the low-density granular pellets were subjected to microencapsulation by an emulsion evaporation technique using ethyl cellulose 7 cps and Eudragit S 100 as coating polymers and 1% w/v polyethylene glycol 400 as aqueous phase. The prepared microballoons were characterized for their particle size analysis, angle of repose, and compressibility index. The in vitro release studies were performed in 0.1 N HCl as medium. The prepared microballoons were free-flowing and spherical in shape. From all the formulations, F5E and F5F can be considered as promising controlled release floating microballoons of stavudine providing first-order release over a period of 12 hours, with a minimum floating lag time of 1 minute. It was found that the ratio of the drug & polymer, stirring speed, and concentration of surfactant were the most significant variables which influenced the size of the stavudine microballoons under the applied experimental conditions.