ANALYSIS OF AMINOPHYLLINE IN THIGH CREAM FORMULATIONS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Aminophylline is a 2:1 mixture of theophylline and ethylenediamine whi ch is widely used as a bronchorelaxant for the treatment of asthma. Mo re recently, it has been claimed that formulations of aminophylline in topical creams are useful for the reduction of lower body fat. As par t of a study of the efficacy of such formulations, we have developed a chromatographic method for the analysis of aminophylline in cream pre parations. The method involves dissolving the creams in an acetone-wat er solvent, derivatizing the aminophylline components with dansyl chlo ride and analyzing the resulting mixtures by reversed-phase high perfo rmance liquid chromatography (HPLC). Because other components of the c reams are separated from the aminophylline components during the HPLC analysis, no extractions of aminophylline from the creams are required . However, vigorous stirring of the reaction mixture during the dansyl ation is required to ensure that all of the aminophylline components a re derivatized. Several commercial aminophylline-based thigh cream for mulations were analyzed by this method. It was found that these formul ations varied significantly in the amount of aminophylline present.