Development and validation of a stability-indicating RP-LC method for famciclovir

A novel stability-indicating gradient reverse phase liquid chromatographic (RP-LC) method was developed for the determination of purity of famciclovir (FCV) in presence of its impurities and degradation products. The method was developed using Inertsil ODS 3 V (250 x 4.6 mm, 5 microm) column with mobile phase containing a gradient mixture of solvent A and B. 0.01 M potassium dihydrogen orthophosphate buffer, pH adjusted to 6.0 with 1% potassium hydroxide was used as buffer. Buffer and methanol in 80:20 (v/v) ratio was used as solvent A and buffer and methanol in 20:80 (v/v) ratio was used as solvent B. The gradient program (T/%B) was set as 0/5, 15/30, 25/50, 45/60, 55/5 and 60/5. The eluted compounds were monitored at 215 nm. FCV was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. FCV was found to degrade significantly in oxidative, acid and base degradation conditions and mildly in hydrolytic degradation conditions and stable in thermal and photolytic degradation conditions. The degradation products were well resolved from main peak and its impurities thus proved the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantitation, precision, linearity, accuracy, robustness and system suitability. This method is also suitable for the assay of famciclovir which ranged from 99.9% to 100.2%.