Formulation and Evaluation of Floating Microspheres by Using Eudragit RSPO

Abstract

Acyclovir floating microspheres using Eudragit RSPO alone or in combination with different viscosity grades of hydroxypropyl methylcellulose were prepared for the purpose of improving the oral bioavailability of acyclovir. Floating microspheres were prepared by using an emulsion solvent diffusion technique. During process optimization various parameters were studied such as: drug: polymer ratio, polymer ratio, concentration of emulsifier and stirring speed. Prepared microspheres were analyzed for particle size, surface morphology, entrapment efficiency, buoyancy, differential scanning calorimetry and in vitro drug release. Microspheres prepared were spherical shaped with smooth surface. Size of microspheres was in the range of 621 to 784µm. The said procedure resulted in formulations with good entrapment efficiency and % buoyancy and controlled release characteristics. The drug polymer ratio and viscosity of HPMC used had a significant effect of the various characteristics of formulation devised.