Formulation design and <i>in vitro</i> characterization of gastroretentive floating acyclovir tablets

Abstract

Acyclovir is a thymidine kinase enzyme inhibitor used in the management of herpes zoster. Doses above 400mg exhibit poor  bioavailability necessitating frequent administration to achieve the required therapeutic serum concentrations. This study aimed to  design, formulate, and characterize floating tablets with enhanced bioavailability due to improved gastric retention time. The simplex  lattice mixture design was employed to guide polymer proportions. Independent variables included polymers HPMC K100M, HPMC K4M,  and Carbopol. The dependent variables were the floating lag time, total floating time and the cumulative drug release at 3, 6, and 8 hours, respectively. Formulation F2 exhibited the most desirable profile with a floating lag time and total floating time of 142 seconds and  14 hours, respectively and cumulative drug release at 3, 6, and 8 hours of 38.3%, 66.0% and 81.2 %, respectively. The findings indicate  the feasibility of fabricating a commercially viable floating acyclovir tablet exhibiting extended gastric retention time and a  controlled drug release profile.