Abstract
Candesartan cilexetil is an angiotensin-receptor blocker, is marketed in combination with hydrochlorothiazide, which is a diuretic acting on distal convoluted tubule; for synergistic anti-hypertensive action. The present study deals with development and validation of a stability indicating HPTLC method for simultaneous estimation of candesartan cilexetil and hydrochlorothiazide using TLC aluminum plate Pre coated with silica gel 60 F254(make: Merk) and the mobile phase comprising ethyl acetate: toluene: methanol: glacial acetic acid (5:2:3:0.1 v/v/v/v). Hydrochlorothiazide and candesartan cilexetil were well resolved with Rf 0.06 ± 0.027 and 0.19 ± 0.031, respectively. The wavelength selected for the quantization was 260 nm. Results: Stress testing for both the drugs was carried out according to International Conference of Harmonization (ICH) guidelines Q2 (R1). The method was successfully validated according to ICH guidelines Q2 (R1). The linear regression analysis indicated a good linear relationship over the concentration range of 160 – 960 ng/spot and 125 – 750 ng/spot for candesartan cilexetil and hydrochlorothiazide respectively, with correlation co efficient value of 0.9993 and 0.9987 for candesartan cilexetil and hydrochlorothiazide respectively. The accuracy of the method was established based on recovery studies. The LOD of candesartan cilexetil and hydrochlorothiazide were found to be 2.1988 and 1.9369 ng/spot and the LOQ of candesartan cilexetil and hydrochlorothiazide were found to be 0.6631 and 5.8723 ng/spot. Among various stressed conditions, candesartan cilexetil and hydrochlorothiazide showed considerable degradation under all the conditions but they are within the limit. The degraded products of hydrochlorothiazide and candesartan cilexetil were well resolved from the individual bulk drug response. Conclusion: The developed method is found to be simple, specific, precise and stability indicating. The specificity of the method was confirmed by peak purity profile of the resolved peaks.
