Indo Global Journal of Pharmaceutical Sciences, 2020; 10(3): 6-20 6 Estimation of Telmisartan, Amlodipine and Chlorthalidone in Bulk and Fixed Dose Combination Using Stability Indicating High Performance Thin Layer Chromatography Bhamini R. Chaudhary 1* , Jayant. B. Dave 2 1 SAL Institute of Pharmacy, Ahmedabad, Gujarat – 380060, India 2 L.M. College of Pharmacy, Ahmedabad, Gujarat – 380009, India Address for Correspondence: Bhamini R. Chaudhary, bhaminisspcqa@gmail.com Received: 30.05.2019 Accepted: 23.12.2019 Published: 24.11.2020 Keywords Telmisartan (TEL); Amlodipine (AML); Chlorthalidone (CHLO); Stability Indicating Assay Method (SIAM); High- performance thin-layer chromatography (HPTLC); fixed dose combination (FDC); Validation (ICH Q2 R1). INTRODUCTION A fixed-dose combination of Telmisartan (40 mg), Amlodipine (5 mg), and Chlorthalidone (12.5 mg) is a very effective three –in –one pill with a minimum risk profile for cardiovascular events and longer duration of action for the treatment of essential hypertension. This FDC offers several advantages and is available under several brand names in India. Telmisartan {4’ – [[4-methyl – 6- (1-methyl – 1 H – benzimidazol -2-yl) – 2- propyl – 1 H- benzimidazol -1- yl] methyl] biphenyl -2- carboxylic acid} (Figure 1) is an angiotensin II receptor antagonist which is used in the treatment of hypertension. Angiotensin II receptor blockers bind to angiotensin II type I receptors and inhibit its effect on vascular smooth muscle, which causes a reduction in arterial blood pressure [1]. It is official in BP [2], USP [3], EP [4] and IP [5]. A literature survey revealed that many methods are reported for the determination of TEL by spectrophotometry [6, 7], HPLC [8, 9], LC-MS/MS [10, 11], and HPTLC [12, 13]. INDO GLOBAL JOURNAL OF PHARMACEUTICAL SCIENCES ISSN 2249- 1023 ABSTRACT: A simple, accurate and precise stability-indicating high-performance thin-layer chromatography was developed and validated for the estimation of Telmisartan, Amlodipine and Chlorthalidone in bulk and pharmaceutical dosage form. Chromatographic separation was carried out on Merck TLC Aluminum plates, pre-coated with silica gel 60 F254 of size (20 cm × 10 cm) with 250 μm layer thickness with the mobile phase Chloroform: Toluene: Methanol: Glacial Acetic Acid (6:2:2:0.1 % V/V/V/V) at detection wavelength 254 nm for TEL, AML and CHLO. The Rf value for TEL, AML, and CHLO were found to be 0.64 ± 0.008, 0.25 ± 0.008 and 0.48 ± 0.01, respectively. The method was linear over the concentration ranges 400-4800 ng/band for TEL, 50-600 ng/band for AML and 125-1500 ng/band for CHLO. The LOD was found to be 19.98 ng/ band for TEL, 5.32 ng/ band for AML and 11.28 for CHLO. The LOQ was found to be 60.55 ng/ band for TEL, 16.12 ng/ band for AML and 34.18 ng/ band for CHLO. Under the forced degradation conditions, TEL degraded significantly under acidic and oxidative stress conditions, degraded moderately under alkaline, thermal and photolytic stress conditions; and showed negligible degradation under neutral hydrolysis condition. AML degraded significantly under acidic, alkaline and oxidative stress conditions, degraded moderately under thermal stress condition and degraded the least under neutral and photolytic stress conditions. CHLO degraded extensively under acid and alkaline stress conditions, degraded moderately under oxidative, thermal and photolytic stress conditions and degraded the least under neutral hydrolysis condition. © 2020 iGlobal Research and Publishing Foundation. All rights reserved. Cite this article as: Chaudhary, B.R.; Dave, J.B. Estimation of telmisartan, amlodipine and chlorthalidone in bulk and fixed dose combination using stability indicating high performance thin layer chromatography. Indo Global J. Pharm. Sci., 2020; 10(3): 6-20. DOI: http://doi.org/10.35652/IGJPS.2020.10302 .