STUDIES ON METABOLISM OF ISONIAZID BY A NEW CHEMICAL DETERMINATION OF ISONIAZID (THE 2 ND REPOR T )

Abstract

Sunahara et al. have reported that t h e frequency distribution curve of the biologically active isoniazid serum levels was trimodal, corresponding to the three patterns of isoniazid metabolism: slow, intermediate and rapid inactivation. They classified the subjects as rapid inactivators if the concentration at 6 hours after the oral dose of 4 mg of isoniazid per kg of body weight was equal to or less than 0.15μg per ml, intermediate if it was between 0. la and 0.8μg per ml, and slow if it was equal to or greater than 0.8μg per ml. But such a classification of isoniazid metabolism obtained by a biological assay method has not yet been confirmed by a chemical assay method. In this study, the investigation on the metabolic patterns in the isoniazid metabolism was undertaken by the chemical assay method of isoniazid which had been devised by Nakagawa, and a few factors participating in the isoniazid metabolism were also studied.