Q-Absorbance Ratio Spectrophotometric Method for the Simultaneous Estimation of Paracetamol and Propyphenazone in their Combined Pharmaceutical Dosage Form

The present manuscript describes simple, sensitive, rapid, accurate, precise and economical Q-absorbance ratio method for the simultaneous determination of Paracetamol and Propyphenazone in their combined pharmaceutical dosage form. Absorbance ratio method uses the ratio of absorbance at two selected wavelengths, one which is an isoabsorptive point and other being the λ-max of one of the two components. Paracetamol and Propyphenazone show an isoabsorptive point at 264 nm in methanol.The second wavelength used is 249 nm, which is the λ-max of Paracetamol in methanol. The linearity was obtained in the concentration range of 1-12 μg/ml for Paracetamol and 5-24 μg/ml for Propyphenazone. The concentrations of the drugs were determined by using ratio of absorbance at isoabsorptive point and at the λ-max of Paracetamol. The method was successfully applied to pharmaceutical dosage form because of no interference. The results of analysis have been validated by recovery studies.