Abstract

A fast, simple and fully automated RP-HPLC analytical method with UV detection for determination of indomethacin substance and its degradation product 4-chlorobenzoic acid was modified and validated. The analysis was performed at isocratic conditions, applying a mobile phase of acetonitrile and 0.5% ortophosphoric acid (50:50, v/v) at flow rate 1.5 ml/min. The system’s suitability parameters and validation parameters were set up.

The modified and validated method was successfully applied for determination of stability of indomethacin substance under a model of physiological conditions. The analyzed indomethacin substance was established to be stable in acid and neutral media, while a hydrolysis occurs in alkali media. A first order rate constant for the degradation of indomethacin in alkali media was determined.