DETERMINATION OF TELMISARTAN HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE IN BINARY MIXTURE AND PHARMACEUTICAL TABLET DOSAGE FORM BY FIRST DERIVATIVE RATIO SPECTROPHOTOMETRIC METHOD

New first derivative ratio spectrophotometric method was developed for simultaneous estimation of telmisartan hydrochloride (TELM) and hydrochlorothiazide (HCTZ) in combined tablet dosage form without prior separation. The amplitude in the first derivative of the corresponding ratio spectra at 263.2 nm and 278.4 nm of TELM and for HCTZ at 287.2 nm and 304.8 nm were selected for the determination. The calibration graphs were established in the range of 1-10μg/mL and 2-15 μg/mL of TELM and HCTZ, respectively. The percentage recoveries of binary mixture of TELM were found to be 97.81±1.05 (263.2nm) and 96.60±1.91 (278.4nm) and for HCTZ were found to be 97.47±1.41 (287.2), 98.16± 1.45 (304.8nm) by proposed method. This method was successfully applied for the analysis of commercial tablet formulation, with no interference from excipients as indicated by the recovery study results. The proposed method was validated, statistically analyzed, compared with reported HPLC method and can be successfully applied for the routine analysis.