Development of a sensitive spectrophotometric method for the quantification of ketotifen fumarate in aqueous solutions via diazotization of 4-aminoantipyrene

Abstract

This study introduces a novel, rapid, and highly sensitive spectrophotometric method for the quantification of Ketotifen fumarate in aqueous solutions. The presented method involves the diazotization of 4-aminoantipyrene utilizing sodium nitrate in an acidic medium, followed by the subsequent coupling of the diazonium compound with Ketotifen in a basic environment. The resultant orange azo dye demonstrates a peak absorbance at 483 nm and possesses solubility and stability in aqueous solution for over 60 minutes. The absorbance of the dye exhibits a linear response within the concentration range of 1–10 µg/mL, with a molar absorptivity of 11,943.84 L·mol⁻¹·cm⁻¹ and a Sandell's sensitivity index of 0.0259 µg/mL. The method conveys exceptional accuracy, with results ranging between 98% and 100.16%, and has been successfully utilized for the analysis of pharmaceutical formulations.