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

Abstract

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 60F254 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 (Rf 0.40± 0.01) and Nebivolol hydrochloride (Rf 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 Rf 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.