Development and Characterization of Floating Microspheres of Acyclovir As Gastroretentive Dosage Form

In the present study, an attempt has been made to prepare floating microspheres of Acyclovir designed as gastroretentive dosage form for the Herpes simplex virus infection as well as vericella zoster infection. The floating microspheres were prepared using Ethylcellulose by Non-aqueous Solvent Evaporation technique which offers advantage of short processing time and gives high encapsulation efficiency. Formulations were characterized for their particle size, practical yield, percentage entrapment efficiency, buoyancy, drug-polymer compatibility (FTIR), Scanning electron microscopy (SEM), in vitro drug release and model fitting kinetics. SEM analysis shows that spherical microspheres with porous surface were formed. The particle size of microspheres was in the range of 262.6±2.52 to 348±2.49µm. Percentage encapsulation efficiency was between 71.6±0.53 to 91.6± 0.32%. Microspheres remained buoyant for more than about 12 h. The results of FTIR spectroscopy indicated the stable character of acyclovir in microspheres and also revealed absence of drug-polymer interaction. The formulation F5 showed results of in vitro drug released (95.56%) and acyclovir microspheres showed release from slow to sustained for more than 10hr. The release obeys zero order model. All the stability studies for the formulation F5 showed no significant change in the percentage drug release studies and percentage buoyancy. The results of factorial batches revealed that the concentration of ethyl cellulose and stirring speed significantly affected drug encapsulation efficiency and particle size of the microspheres. Thus we can conclude that floating microspheres can successfully be developed to sustain the drug release.