A new method for the spectrophotometric determination of fexofenadine hydrochloride

Abstract

A novel, sensitive and selective reaction has been proposed for the assay of fexofenadine hydrochloride (FFH) in bulk and dosage forms using chloramine-T (CAT) and two dyes malachite green (MAG) and xylene cyanol FF (XFF). Spectrophotometric method entail the addition of a known excess of chloramine-T to fexofenadine hydrochloride in hydrochloric acid medium followed by the determination of residual oxidant by reacting it with a fixed amount of malachite green, measuring the absorbance at 615 nm (method A), or xylene cyanol FF, measuring the absorbance at 612 nm (method B). The apparent molar absorptivities are calculated to be 4.09×10⁴ L mol^-1 cm^-1, 3.07×10⁴ L mol^-1 cm^-1for method A and B respectively. Both methods are of comparable accuracy and precision. There is no interference from common additives and excipients. The method has been applied to the determination of fexofenadine hydrochloride in pharmaceutical samples and the results are statistically compared with those of literature UV-spectrophotometric method by applying student’s <i style="">t</i>-test and <i style="">F</i>-test.