Development of an Assay for Acyclovir in Pharmaceutical Preparation and Human Plasma by HPLC

Abstract

A reversed phase HPLC method was developed to separate acyclovir (antiviral agent) from its major related impurities, guanine and its major metabolite 9-carboxy methoxy methyl guanine (CMMG) base. These agents may participate in a number of interaction including formation of neutral ion-pair and complexation with stationary phase silanols. In optimizing the separation of acyclovir from its degradation product and plasma, stepwise optimization was carried out. The effect of concentration of acetonitrile (ACN), methanol as the organic modifiers, on the retention of acyclovir were examined. The effect of the mobile phase and pH on the retention and peak shape for acyclovir and guanine was also examined and its influence on the capacity factor at constant concentration. The results show the best improvements in peak shape at pH 2.5. The method developed in selective, precise, reproducible and accurate and meets the need of pharmacokinetics studies.