Quantitation of Ethacrynic Acid by High-Pressure Liquid Chromatography

Abstract

A stability-indicating assay method for ethacrynic acid based on high pressure liquid chromatography was developed. The method developed is sensitive, accurate and precise (standard deviation based on 6 readings was ± 1.5%). It was used to study the stability of ethacrynic acid in various aqueous systems. The stability tests were conducted at room temperature as well as at 65°, at various pH values and using different vehicles. The data were treated mathematically to estimate various K values. It has been shown that ammonium ion causes a fast reversible decomposition of ethacrynic acid. Formaldehyde appeared to be one of the products of decomposition.