Absorbances Ratio Method (Isoabsorptive Point) for Determination of Drotaverine Hydrochloride and Ranitidine Hydrochloride from Pharmaceutical Dosage Forms

A simple, reproducible and efficient method for the simultaneous determination of drotaverine hydrochloride and ranitidine in pharmaceutical dosage form was developed. Drotaverine hydrochloride and ranitidine in combination are available as tablet dosage forms in the ratio of 1:3.75. The proposed method is based on the Absorbances ratio method. From overlain of absorption spectra, wavelength 324.4 nm ((isoabsorptive point)) and 351.4 nm were selected for the construction of absorbance ratio equation. The linearity was observed in the concentration range of 2–60 μg/ml for drotaverine hydrochloride and 2–32 μg/ml for ranitidine at given wavelengths. Both the drugs obey Beer's law. The method was validated as per ICH guidelines. The recovery studies confirmed the accuracy of the proposed methods.