Abstrakt

Validated Spectrophotometric Methods for Estimation of Telmisartan and Hydrochlorothiazide in Combined Tablet Dosage Form.

Chinmaya C Behera, Vishal Joshi, Sujit Pillai, and Gopkumar P

Quantitative Spectrophotometric analysis of poorly water-soluble drugs involves use of various organic solvents, solubility enhancing agents, co solvents or Buffers. Major drawbacks of organic solvents include high cost, volatility and toxicity. On the other hand use of alkali or acids may reduce the stability of analytes throughout the process of estimation. In the present investigation, co-solvency technique has been employed to solubilize the poorly water-soluble drugs. Four perspicacious spectrophotometric methods for simultaneous estimation of Telmisartan (TEL) and Hydrochlorothiazide (HCTZ) in two component solid dosage forms have been developed. The methods employed Simultaneous Equation Method and Multicomponent mode of analysis at 295nm and 273nm (absorbance maxima of Telmisartan and Hydrochlorothiazide respectively), the Absorbance Ratio (Q-analysis) method at 283.0nm (iso-absorptive point) and 293.0nm (absorbance maxima of Telmisartan), the First Order Derivative Spectroscopy method at 273.0 nm for Telmisartan (zero cross for HCTZ) and 295.0 nm for Hydrochlorothiazide (zero cross for TEL). The methods utilized Methanol: Water (1:1) as a solvent and were found to be linear in the range of 4-24 μg/ml and 2-14 μg/ml for TEL and HCTZ respectively. The procedures were successfully applied for the simultaneous determination of both drugs in laboratory mixtures and in commercial tablet formulation.