Electrochemical reduction of ketoprofen and its determination in pharmaceutical dosage forms by differential-pulse polarography

A simple differential-pulse polarographic method has been developed for the determination of ketoprofen in dosage forms. Methanol was employed as the solvent for extracting the drug from the formulations, and Britton-Robinson buffer (pH 6.0) containing 5%V/V methanol was used as the supporting electrolyte. The EP occurs at – 1.15 V. Results obtained by the proposed method are in excellent agreement with those provided by the manufacturer's laboratory. Commonly used tablet excipients and suppository bases were found not to interfere. A mechanism for the electrochemical reduction of ketoprofen at – 1.25 V is proposed that involves the transfer of two electrons.