Development and Validation of Spectrophotometric Method for Estimation of Cetirizine Hydrochloride and Phenylephrine Hydrochloride in Combined Dosage Form.

UV-spectrophotometric Q-Absorbance ratio method has been developed and validated for determination of cetirizine hydrochloride and phenylephrine hydrochloride in tablet dosage form. This method involves formation of Qabsorbance equation at two wavelengths i.e. isobestic point (230.0 nm) and λmax of phenylephrine hydrochloride (272.80 nm). The linearity was observed in the concentration range 5–30μg/ml for both the drugs at selected wavelengths, correlation coefficient (r²<1). Accuracy was confirmed by recovery studies and precision by marketed formulation analysis. % R.S.D. values for ruggedness studies were less than 2% indicated reproducibility of the method. Commercial tablet formulation was successfully analyzed using the developed method.