Spectrophotometric determination of mefenamic acid in pharmaceutical preparations

The present paper describes an effective and low-cost spectrophotometric method for the determination of mefenamic acid in its pure form and pharmaceutical preparations. The method is based on the charge-transfer complexation between mefenamic acid as an n-electron donor and chloranil as a n-acceptor to form a violet chromogen measured at 540 nm. Under the optimum conditions, a linear relationship with a good correlation coefficient (0.9996) was found between the absorbance and concentration of the studied drug in the range of 10-60 mu g/mL. The optimal reaction conditions such as reagent concentration, heating time, and stability of the reaction product were determined. The limit of detection (LOD) was 2.16 mu g/mL and the limit of quantification (LOQ) was 7.15 mu g/mL. The method was successfully applied to the determination of mefenamic acid in pharmaceutical preparations without any interference from common excipients.