DEVELOPMENT AND VALIDATION OF FTIR SPECTROSCOPIC METHOD FOR SIMULTANEOUS ESTIMATION OF TELMISARTAN AND HYDROCHLOROTHIAZIDE IN PURE AND PHARMACEUTICAL DOSAGE FORMS

A new analytical method has been developed for the simultaneous estimation of Telmisartan and Hydrochlorothiazide in their pure and pharmaceutical dosage forms by using Fourier Transform Infrared (FTIR) Spectroscopy. This method involves the extraction of Telmisartan and Hydrochlorothiazide from tablets using chloroform and direct measurement in liquid phase mode using reduced path length cell. The spectra were measured in absorbance mode, equipment was configured to collect spectra at 8 cm^-1 resolution, and the spectra were collected between 4000 cm^-1 and 450 cm^-1. The infrared spectra showed different peaks with baseline correction, among which intense, clear and proportionate peaks were selected at 3411 cm^-1, and 1309 cm^-1 corresponding to the N-H group and asymmetric SO₂ group for Telmisartan and Hydrochlorothiazide respectively for quantitative estimation. Beer-Lambert’s law was obeyed over the concentration range of 50-250 μg/ml for Telmisartan and 25-125 μg/ml for Hydrochlorothiazide. All the results were found to be within the limits. The results obtained were compared statistically with that of HPLC by t-test, which indicated no significant difference between the methods at the probability value of 0.05. Therefore, it can be used for routine quality control of these two drugs in bulk and formulations.