[Pharmacokinetics of dihydralazine following intravenous administration in laboratory animals]

Comparative pharmacokinetic studies with high i.v. doses of dihydralazine (1, 5 and 7.5 mg/kg-1, respectively) were performed in rats, rabbits, and dogs. 1 was distributed in rabbits and dogs in two phases with half lives of 0.25-0.4 min and 1.0-2.0 min. The terminal slope was species dependent. The relative clearance values decreased in the order rabbit, rat, dog. High tissue concentrations were observed in rabbits and dogs in parenchymatous organs and endothelium (aorta). Skeletal and heart muscles belonged to the central compartment. The biliary excretion was low in rabbits. Dogs accumulated the drug in bile (bile/serum-ratios = 19-390). Maximally 5% of the given dose were excreted in rabbits with the 12-h-urine.