Indirect Spectrophotometric Method for the Determination of Mefenamic Acid in Pharmaceutical Formulations*

Abstract

A simple, sensitive and accurate spectrophotometric method for the determination of mefenamic acid in pure form and in some pharmaceutical formulations was developed. The method is based on the oxidation of mefenamic acid by iron(III), and subsequent complexation of iron(II) with o-phenanthroline, forming a red-colored complex (ferroin) having the maximum absorbance at 510 nm. Beer's law is obeyed in the concentration range of 0.4-2.0 µg\ml, the molar absorptivity and Sandell's sensitivity are 2.9×10 4 L.mol -1 .cm -1 and 8.3 ng.cm -2 , respectively and the relative standard deviation (RSD) is less than 2.0 (n=10). The limits of detection and quantitation are 0.065 and 0.195 µg.ml -1 ,respectively. The method is applied successfully to determination of mefenamic acid in some pharmaceutical formulations (capsules and tablets). The common excipients do not interfere with the proposed method. A statistical comparison of these results with those of official method using (t and F) values at 95% confidence level shows good agreement and indicates no significant difference in the precision and the present method has good validity.

Review for Analytical Methods for the Determination of Mefenamic Acid

“…The method involves the oxidation of MFA by iron(III) followed by the complexation of iron(II) with ophenanthroline resulting in a red-colored complex (ferroin) with a maximum absorbance at 510 nm. Beer's law is obeyed in the concentration range of 0.4-2.0 µg/ml [21]. Raju Chandra et al developed validation for the estimation of MFA from marketed tablet and the λmax was found to be 370 nm, the limit of detection and limit of quantification was 0.3 and 0.9 ppm respectively.…”

Determination of Mefenamic Acid in Aqueous Solutions Using Reverse - Continuous Flow Injection Analysis

“…Through repeatable and accurate timing, the FI approach can measure the properties of metastable and transitory species. Multiple measurements developed for clinical, pharmacological, dietary, and environmental studies have demonstrated the value of FI methods for regular analysis [10,[16][17][18][19][20][21][22][23][24][25][26]. When the reagents used are expensive, and the model is cheap and available in large quantities, it is preferable to reverse the injection process.…”