Pharmacokinetic studies of trimethadione and its metabolite in rats with chemical-induced liver injury.
A rapid and sensitive gas-liquid chromatographic procedure was developed for the measurements of trimethadione (TMO) and its metabolite, 5, 5-dimethyl-2, 4-oxazolidine-dione (DMO) in plasma. TMO and DMO were extracted from plasma by a micro-extraction method and chromatographed on a 10% Carbowax 6000 column using paramethadione as an internal standard. Recoveries of TMO and DMO ranged from 96 to 104% using a 0.1 ml of plasma. The method is capable of measuring at least 5 microgram of TMO and DMO per milliliter. After an oral administration of TMO at a dose of 100 mg/kg, mean plasma levels of TMO and DMO in 6 rats reached a peak of 98 microgram/ml at 0.6 h and 163 microgram/ml at 8 h and declined with a half-life of 2.2 h and 39.4 h, respectively. After the intravenous administration of TMO at a dose of 100 microgram/kg, half-lives of TMO and DMO were 2.5 h and 39.1 h, respectively. Pretreatment of rats with carbon tetrachloride, d-galactosamine amd alpha-naphthyl isothiocyanate, prolonged T 1/2 and Tmax of TMO, reduced the Km value and increased the AUC. These results suggest that plasma levels of TMO and DMO might be useful as an index of drug metabolizing capacity in animal and man.
D015058:1-Naphthylisothiocyanate / Q000633:toxicity; D000284:Administration, Oral; D000818:Animals; D001711:Biotransformation; D002252:Carbon Tetrachloride Poisoning / Q000378:metabolism; D056486:Chemical and Drug Induced Liver Injury / Q000378:metabolism*; D004114:Dimethadione / Q000097:blood*; D005688:Galactosamine / Q000633:toxicity; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D010080:Oxazoles / Q000097:blood*; D051381:Rats; D013997:Time Factors; D014293:Trimethadione / Q000008:administration & dosage / Q000097:blood*
D010080:Oxazoles; D015058:1-Naphthylisothiocyanate; D005688:Galactosamine; D004114:Dimethadione; D014293:Trimethadione