Evaluation of the Influence of Stirring Speed on the Release Kinetics of Fexofenadine HCl Polymeric Microspheres

Abstract

Microspheres, a potential drug delivery approach, has opened a new era for attaining versatile release patterns needed. By optimizing the formulation variables, they can be prepared to obtain targeted release, immediate release, sustained release patterns. The release of the active drug material depends upon a number of formulation parameters such as polymers, stirring speed (rpm), methodology, surfactants, etc. Fexofenadine hydrochloride (HCl) is a second generation antihistamine. Our present research has explored the effects of using different rpm (600- 1000 rpm) in preparing fexofenadine hydrochloride (HCl) microspheres by emulsion solvent evaporation method. The formulation is aimed to provide sustained release for the required long period with a high margin of safety. We used a blended mixture of Hydroxy Propyl Methyl Cellulose (HPMC) K 100 MCR and Eudragit RL100 polymers to have sustained-release microspheres. The impact of different rpm on Yield, drug encapsulation efficiency, flow properties, and dissolution pattern were appraised. We observed the release of the drug for 10 hours in phosphate buffer (pH 6.8) and evaluated the drug release spectrophotometrically. Our study finds that the release of fexofenadine HCl from the microspheres was significantly increased with drug loading. We found the dosage forms to follow Higuchi release kinetics and Hixson-Crowell release kinetics the most, indicating successful achievement of sustained-release pattern in the dosage form. The change in drug release rate was statistically significant for variation in the stirring rate. We found that 600 rpm was the most optimized stirring rate for preparing microspheres in the emulsion solvent evaporation method.