Stability Indicating HPTLC Method for Estimation of Nebivolol Hydrochloride and Amlodipine Besylate in Combination

A sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method of analysis of Amlodipine besylate and Nebivolol hydrochloride both as a bulk drug and in formulations containing these two in combination was developed and validated. The method employed TLC aluminum plates precoated with silica gel 60F(254) as the stationary phase. The solvent system consisted of Ethyl acetate: Methanol: Dilute ammonia (8.5:1:1, v/v/v). This system was found to give compact spots for Amlodipine besylate (R-f 0.40 +/- 0.01) and Nebivolol hydrochloride (R-f 0.60 +/- 0.02). Amlodipine besylate and Nebivolol hydrochloride were individually subjected to stress degradation conditions like oxidation, dry heat treatment, photo degradation and hydrolysis under different pH. The peaks of products formed during stress degradation studies were well resolved from the bulk drug peak with significantly different R-f values. Densitometric analysis of Amlodipine besylate and Nebivolol hydrochloride was carried out at 240 and 280 nm respectively. The linear regression analysis data showed good linear relationship in the concentration range 500-2000 ng spot (-1) for both Amlodipine besylate and Nebivolol hydrochloride. The method was validated for linearity, accuracy, specificity, LOD, LOQ, precision and robustness. The limits of quantitation for Amlodipine besylate and Nebivolol hydrochloride were found to be 313 and 277 ng spot (-1) respectively. The statistical analysis proved that the method is repeatable and selective for the estimation of the said drugs. As the method could effectively detect the drugs in the presence of their degradation products, it can be employed as a stability indicating one.