Matsuki Y, Katakuse Y, Matsuura H, Kiwada H, Goromaru T
Faculty of Pharmaceutical Sciences, University of Tokushima, Japan.
Chem Pharm Bull (Tokyo). 1991 Feb;39(2):445-8. doi: 10.1248/cpb.39.445.
We examined the effect of glucose (Glu) and ascorbic acid (AA) on absorption and metabolism of isoniazid (INAH). After p.o. administration of INAH with or without Glu or AA, plasma concentration and urinary excretion of INAH and its metabolites, acetyl INAH (AcINAH), acetyl hydrazine (AcHy) and hydrazine (Hy), were determined by means of gas chromatography-mass spectrometry using stable isotope labeled compounds as internal standard. The combined administration of INAH with Glu or AA led to a significant decrease in the excretion of INAH and Hy, and a significant increase in the excretion of AcINAH and AcHy. The absorption amount of INAH was reduced to about one-half by the addition of Glu and the absorption rate of INAH markedly decreased in the case of co-administration of AA. Comparing the oral case with the results of i.v. administration, Glu and AA only affect the absorption process containing the first pass metabolism of INAH.
