Preparation of Acyclovir Controlled-Release Tablets Using Blend of Hydrophilic/Hydrophobic Polymers: an Approach for Better Patient Compliance

Abstract

This study was carried out to formulate and evaluate controlled release (CR) matrix tablets of
acyclovir using combination of hydrophilic and hydrophobic polymers. Acyclovir is a guanine derivative and
is its half-life is short hence administered five times a day using immediate release tablets. Six formulations
(F1-F6) were developed using ethocel and carbopol in equal combinations at drug-polymer (D:P) ratio of
10:5, 10:6, 10:7, 10:8, 10:9, and 10:10. Solubility study was performed using six different solvents. The compatibility studies were carried out using FTIR and DSC. According to USP, Quality Control and dimensional
tests (hardness, friability, disintegration and thickness) were executed. In vitro drug release studies of acyclovir were carried out in dissolution apparatus using using 0.1 N HCl medium at constant temperature of
37 ± 0.5 °C. In order to analyze the drug release kinetics, five different mathematical models were applied to
the release data. The results showed that there was no incompatibility between drug and polymers. Physical
QC tests were found within limits of USP. The release was retarded upto 24 h and non-fickian in vitro drug
release mechanism was found. A formulation developed using blend of polymers, showed excellent retention
and desired release profiles thus providing absolute control for 24 h