Development and validation of a stability-indicating RP-HPLC method for quantitative determination of vasicine in Adhatoda zeylanica leaves and commercial herbal formulations.

A stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for quantitative estimation of vasicine, a major quinazoline alkaloid, in Adhatoda zeylanica leaves and commercial herbal formulations. Chromatographic separation was achieved on a C18 column using a methanol-water mobile phase at a flow rate of 1.0 mL/min with UV detection at 289 nm. The method showed linearity over 4-20 µg/mL (r2 = 0.997), with recovery values of 97%-99% and %RSD below 2%. The LOD and LOQ were 0.5 µg/mL and 0.8 µg/mL, respectively. Forced degradation studies under acidic, alkaline, oxidative, thermal, wet heat, and photolytic conditions confirmed the stability-indicating nature of the method. The method was successfully applied to marketed herbal formulations, demonstrating suitability for routine quality control.