Formulation Development and Evaluation of Floating Microsphere of Acyclovir

The guanine derivative antiviral drug acyclovir (ACV) is one of the oldest molecules laying successful market until date, bei ng commercially available in various dosage forms for oral, topical and parenteral administrations. Clinical application of this drug is superior to new antiviral agents due to its potential values such as suppression of recurrence, safety profile, minimal drug interactions and being inexpensive. ACV is slightly water soluble, less permeable and poorly bioavailable, yet more potential antiviral molecule. The present study involves preparation and evaluation of floating microspheres using ACV as a model drug for improving the drug bioavailability by prolongation of gastric retention time. Ethyl cellulose, hydroxyl propyl methyl cellulose microspheres loaded with ACV were prepared by solvent diffusion evaporation method. The microspheres had smooth surfaces with free-flowing and good-packing properties. The yield of the microspheres (F1-F6) was range from 62.23±0.85 to73.32±0.65% and ethyl cellulose microspheres entrapped the maximum amount of the drug. Scanning electron microsco py confirmed their hollow structures with sizes in 198.3 nm. The prepared microspheres (F3) exhibited prolonged drug release and percentage buoyancy was found to 76.65±0.52. The formulated batches were evaluated for percentage yield, particle size measurement, flow properties, percent entrapment efficiency, swelling studies. The formulations were subjected to stability studies and In-vitro release and release kinetics data was subjected to different dissolution models. It was concluded that developed floating microspheres of ACV offers a suitable and practical approach for prolonged release of drug over an extended period of time and thus oral bioavailability, efficacy and patient compliance is improved.