Stability indicating HPTLC method for simultaneous determination of Azelnidipine and Telmisartan combined tablet dosage form

Abstract

The combination of azelnidipine (AZL) and telmisartan (TLM)is widely used in the treatment of hypertension. A simple, rapid, precise, selective and accurate stability indicating High-Performance Thin-Layer Chromatographic (HPTLC) method was developed and validated for their simultaneous estimation of Azelnidipine and Telmisartanin its combined tablet formulation. Stationary phase used is TLC aluminium plates precoated with silica gel 60F-254.The mobile phase consists of Chloroform: Ethylacetate (5:5 v/v) and 10 ml of mobile phase was used per chromatography run. It provides well defined spots for both azelnidipine (Rf value 0.70) and telmisartan (Rf value 0.17) and the degraded products were clearly separated from pure drugs. Densitometric scanning was performed using a Camag TLC scanner 3 in the reflectance absorbance mode at 254 nm by Wincats software. The calibration plot showed good linearity with r² = 0.9967 in the concentration range of 1-6 μg/ml for Azelnidipine and 5 -30 μg/ml for Telmisartan with r² =0. 9966.The method was validated for accuracy, precision, recovery and robustness and it was found to be linear, accurate, specific. precise, robust and stability indicating for routine analysis of both the drugs in simultaneous estimation. Percentage assay was found to be 98.87 and 100.17 for Azelnidipine and Telmisartan. The % RSD for intraday studies of AZL and TLM 0.0184 and 0.0068 respectively. The % RSD for interday studies of AZL and TLM was found to be 0.0126and 0. 0068. The LOD for AZL and TLM was found to be 910 μg/ml and 4570μg/ml. The LOQ for AZL and TLM was found to be 276 μg/ml and 13850μg/ml. Drugs were subjected to acid and base hydrolysis, oxidative, photo and thermal degradation as per ICH recommended conditions. The drug undergoes degradation under acidic, base, oxidative and heat degradation but no degradation observed for both the drugs under photo and neutral degradation (water). As the method could effectively separate drug from its degradation products it can be employed as stability indicating one. The reported method is simple, selective, timesaving, and economic compared to other HPLC methods reported.