Stability indicating HPTLC method for quantitative estimation of manidipine sihydrochloride API

A simple, selective, precise and stability indicating high performance thin layer chromatographic method has been established and validated for analysis of manidipine hydrochloride in bulk. The compound was analyzed on aluminium backed silica gel 60 F254 plates with methanol:water, 8.5:1.5 (v:v) as mobile phase. The system was found to give compact spots for manidipine dihydrochloride (RF=0.75). Densitometric analysis was performed at 230 nm. Regression analysis data for the calibration plot indicated good linear relationships between response and concentration over the range of 500-3000 ng/spot. The correlation coefficient, r2 was 0.998. The values of slope and intercept of the calibration plot were 2785.5 and 62.314, respectively. The method was validated for precision, recovery and robustness. The limits of detection and quantification were 20 and 50 ng, respectively. Manidipine dihydrochloride was subjected to acid, base, peroxide and sunlight induced degradation. In stability test the drug was susceptible to acid and base hydrolysis, oxidation and photodegradation. Statistical analysis proved that the method is repeatable, selective and accurate for manidipine. Because the method could effectively separate the drug from their degradation products, it can be used as a stability indicating method.