[Pharmacokinetics of rifamycin].

Rifamycin pharmacokinetics was studied on experimental animals after the antibiotic administration by various routes. Parenteral use of the antibiotic resulted in its high levels in rats and rabbits. Irrespective of the administration route, i. e. intravenous, intramuscular or oral rifamycin satisfactorily penetrated into the rat tissues. The highest antibiotic levels were found in the animal liver. In small amounts the antibiotic was excreted with the urine (about 6 per cent for 4 hours). The extrarenal clearance of rifamycin was lower than the plasmic clearance only by 3 per cent and higher than the kidney clearance almost by 40 times. Rifamycin was bound in close amounts by the blood serum of humans, oxen and rabbits, i. e. by 68, 64 and 56 per cent respectively. The rat organ homogenates bound the antibiotic by 34--72 per cent.