[Absorption, distribution, and excretion of arbekacin after intravenous and intramuscular administration in rats].

Absorption, distribution, and excretion of arbekacin (HBK) were studied in rats after intravenous or intramuscular administration of HBK at a dose of 10 mg/kg or 20 mg/kg. Elimination half-lives of HBK were 0.69 hour for bolus intravenous administration, 0.55 hour for constant rate intravenous infusion, and 0.57 hour for intramuscular administration. Cumulative urinary excretions within 24 hours after administration were 74.7% of the dose for bolus intravenous administration, and 79.1% of the dose for intramuscular administration. No significant difference was observed in the cumulative urinary excretions between the 2 administration routes. Cumulative biliary excretions within 24 hours after administration were around 0.1% of doses regardless administration routes, bolus intravenous or intramuscular administration. The tissue or organ distribution of HBK after bolus intravenous administration was similar to that after intramuscular administration. The drug was distributed most abundantly into the kidney followed by plasma and the lung. The distribution of the drug into the liver was the least among the 6 tissues or organs examined in this study. The protein binding of HBK was studied by an equilibrium dialysis method at three different concentrations of HBK, 5, 10, and 20 micrograms/ml. Binding ratios of HBK to human serum, human serum albumin, and rat serum were less than 15%.