Thiamphenicol disposition in pigs

Pharmacokinetic parameters of thiamphenicol (TAP) were determined after int ravenous (i.v.) and intramuscular (i.m.) administration of 30 mg kg(-1) of TAP in pigs. Plasma drug concentrations were determined by high performance liquid chromatography (HPLC) Intravenous TAP kinetics were fitted to a hi- exponential equation, with a first rapid disposition phase followed by a sl ower disposition phase. Elimination half-life was short, at 59.3 (29.4) min utes: volume of distribution at steady state was 0.62 (0.24) 1 kg-l; and pl asma clearance was 13.4 (4.5) ml min(-1) kg(-1). After i.m. administration, the peak plasma concentration (C-max = 4.1 mu g ml(-1)) was reached in abo ut 60 minutes; these concentrations are lower than those reported in other species. The TAP elimination half-life after i.m. administration, 250.2 (10 7.1) minutes was longer after than i.v. administration, probably due to the slow rate of absorption from the muscle. The mean bioavailability value fo r i.m. administration was 76 (12) per cent.