[Pharmacokinetic study of apalcillin after infusion]

Apalcillin is a new semi-synthetic penicillin of the uridino-penicillin group. The study comprises two groups of 6 subjects receiving 1 g and 2 g respectively of apalcilline by a two-hour infusion. The assays done by HPLC and microbiology show a good correlation between the two methods. The serum concentrations at the end of the infusion are: 32,2 micrograms/ml-1 (1 g) and 62,7 micrograms/ml-1 (2 g). The modelisation of the serum curves has been realized according to an open model with two compartments. A phase of rapid distribution is observed: t 1/2 alpha of 19.5 mn (1 g), 8.96 mn (2 g) followed by a phase of longer elimination: t 1/2 beta of 1.17 h (1 g), 1.15 h (2 g). The distribution volume at the steady-state is: 14.19 l (1 g), 14.76 l (2 g). This volume, much greater than the plasmatic volume, allows to suppose a good tissular diffusion of apalcilline. The urinary concentrations of the twelve first hours are: 182.64 micrograms/ml (1 g), 323 micrograms/ml (2 g). The urinary elimination during the 24 hours following the administration is: 18.58% (1 g), 16.47% (2 g).