title: Plasma concentrations and pharmacokinetics of dihydralazine after single oral doses to human subjects.
abstract: After single oral doses of 20 mg of a suspension of dihydralazine sulphate to human subjects, the peak of mean plasma concentrations of dihydralazine of 47.0 ng ml-1 +/- 11.0 standard deviation (S.D.) (n = 7) was reached at 1 h. Mean concentrations declined biphasically with apparent half-lives of 0.57 and 4.96 h respectively. Dihydralazine was partly converted to hydralazine. The peak of mean plasma concentrations of the latter drug of 3.9 ng ml-1 +/- 1.7 S.D. (n = 7) occurred at 1-2 h after dosing with dihydralazine sulphate and declined to 1.5 ng ml-1 +/- 1.5 S.D. at 6 h. Of the seven subjects studied, three were classified as fast and four as slow acetylators. Mean clearances appeared to be slightly more rapid in fast acetylators (1.63 l min-1 +/- 0.32 S.D.) when compared to slow acetylators (1.31 l min-1 +/- 0.31 S.D.) but this difference and differences in plasma concentrations and in areas under the plasma drug concentration-time curves were not significant (p > 0.1).
mesh_terms: D000107:Acetylation; D000293:Adolescent; D000328:Adult; D001711:Biotransformation; D004078:Dihydralazine / Q000097:blood*; D006207:Half-Life; D006801:Humans; D006830:Hydralazine / Q000031:analogs & derivatives* / Q000378:metabolism; D007700:Kinetics; D008297:Male; D010641:Phenotype
chemical_list: D006830:Hydralazine; D004078:Dihydralazine