Pharmacokinetics of D(+)-usnic acid in rabbits after intravenous and oral administration.
The pharmacokinetics of D(+)-usnic acid--a lichen antitubercular, antitumor, and enzyme-inhibiting agent--was studied in rabbits following intravenous or oral administration of 5 and 20 mg/kg body weight doses, respectively. Plasma samples were collected at different time intervals, and usnic acid was determined by HPLC. Plasma usnic acid levels following intravenous administration showed a triexponential elimination with a mean +/- SD terminal half-life of 10.7 +/- 4.6 hr. The volume of distribution of the central compartment and systemic clearance were 43.9 +/- 21.3 ml/kg and 12.2 +/- 3.0 ml/hr/kg, respectively. Pharmacokinetic parameters obtained, based on compartmental and noncompartmental approaches, were comparable. Plasma concentration data obtained after oral administration were analyzed using a noncompartmental method. Peak plasma level (Cmax) of 32.5 +/- 6.8 micrograms/ml was achieved in 12.2 +/- 3.8 hr (tmax). Mean absolute bioavailability of usnic acid following oral administration was 77.8%.
Department of Clinical Pharmacology and Therapeutics, Nizam's Institute of Medical Sciences, Hyderabad, India.
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Krishna
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Venkataramana
D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001572:Benzofurans / Q000008:administration & dosage / Q000493:pharmacokinetics*; D007275:Injections, Intravenous; D008297:Male; D011817:Rabbits
D000900:Anti-Bacterial Agents; D001572:Benzofurans; C073339:usnic acid