Abstract

DEVELOPMENT AND VALIDATION OF Q-ABSORBANCE RATIO METHOD FOR SIMULTANEOUS ESTIMATION OF TELMISARTAN AND HYDROCHLOROTHIAZIDE IN MARKETED FORMULATIONS BY DIFFERENCE SPECTROPHOTOMETRY

R. Padmavathi, Y. Padmavathi*, N. Raghavendra Babu, A. Suneetha and B. Guru Sai Supriya

ABSTRACT

A simple Absorbance ratio method was developed and validated for the simultaneous estimation of telmisartan (TELM) and hydrochlorothiazide (HCTZ) in fixed dose combination tablets by difference spectrophotometry technique in the UV region. The absorbance ratio method uses the ratio of absorbance at two selected wavelengths; one is the isoabsorptive point of two components and the other is the λ-max of one of the two components. The difference in spectral characteristics for both the drugs was observed in 0.01N acetic acid and 0.01N NaOH using methanol as solvent. The difference absorbance was measured at 240nm and 308nm for HCTZ and TELM respectively. The method was validated according to ICH guidelines. Linearity range was observed over the concentration range of 5-25μg/ml for hydrochlorothiazide and 10-50 μg/ml for telmisartan. The accuracy and precision of the method were determined and validated statistically. The method showed good repeatability with a %RSD less than 2. The limit of detection and limit of quantization was found to be 0.9μg/ml and 2.7μg/ml for HCTZ and 2.3μg/ml and 7.2μg/ml for TELM at 240nm and 308nm respectively. The validated method was successfully applied for the analysis of hydrochlorothiazide and telmisartan in fixed dose combination tablets.

Keywords: UV region, Hydrochlorothiazide, Telmisartan, Absorbance ratio method, repeatability, ICH guidelines.