PHARMACOKINETICS OF AMOXICILLIN CLAVULANIC ACID COMBINATION AND OF BOTH DRUGS ALONE AFTER INTRAVENOUS ADMINISTRATION TO GOATS/

The pharmacokinetic behaviour of an amoxicillin/clavulanic acid combin ation (25 mg kg(-1)), and both drugs alone (amoxicillin 20 mg kg(-1)), clavulanic acid 5 mg kg(-1)), was studied after intravenous (i.v.) ad ministration of single doses to 10 goats. The objective was to determi ne whether there were differences in the plasma kinetics of these drug s when administered in combination or alone. The plasma concentration- time data were analysed by compartmental pharmacokinetics and noncompa rtmental methods. The disposition curves for both drugs alone and in c ombination were best described by a biexponential equation (two-compar tment open model). The elimination half-lives of amoxicillin were 1.05 +/-0.09 h alone and 1.13+/-0.19 h in combination, and those of clavula nic acid were 0.87+/- 0.07 h and 0.85+/-0.09 h, respectively. The appa rent volumes of distribution of amoxicillin and clavulanic acid were s imilar in the two treatments. Body clearances of amoxicillin were 0.12 +/-0.01 l h(-1) . kg alone and 0.11 +/- 0.01 l h(-1) . kg in combinati on, and of clavulanic acid were 0.12 +/- 0.02 l h(-1) . kg alone and 0 .12 +/- 0.01 l h(-1) . kg in combination with amoxicillin. The half-li ves and body clearances of amoxicillin and clavulanic acid did not dif fer significantly when administered alone and in combination. It was c oncluded that the i.v. administration of amoxicillin and clavulanic ac id as a combination product did not alter the disposition kinetics of either drug.