Determinação espectrofotométrica de cefalexina em formulações farmacêuticas explorando a sua reação de transferência de carga com a quinalizarina Spectrophotometric determination of cephalexin in pharmaceutical formulations exploring its charge transfer reaction with quinalizarin

Abstract

This work proposes a new simple and fast spectrophotometric method for cephalexin determination in pharmaceutical formulations. The method is based on the charge transfer reaction between cephalexin and quinalizarin in dimethylsulfoxide medium. Several analytical parameters related to the system were optimized and the reaction was characterized in terms of stoichiometry. Also, association constant and apparent molar absorptivity of the product were determined. The method presented a limit of detection of 0.46 mg L-1 and a quantification limit of 1.5 mg L-1. It was successfully applied in the determination of cephalexin in two samples of commercial pharmaceutical formulations.

Keywords

• cephalexin
• charge transfer reaction
• spectrophotometry