Effects of experimentally induced Streptococcus suis infection on the pharmacokinetics of penicillin G in pigs

Abstract

The pharmacokinetics of potassium penicillin G were studied in both healthy (n = 8) and experimentally Streptococcus-suis-infected (n = 6) pigs following intramuscular administration (15,000 iu/kg). Streptococcus-suis infection was induced artificially in young cross-bred pigs by subcutaneous inoculation with 9 x 10(8) to 10(9) colony-forming units of S. suis. The rectal temperature of infected pigs was significantly increased (P less than 0.01) before penicillin G injection and this was maintained for 8 h after the drug was given. Other clinical symptoms were also present. The serum concentration-time data for penicillin were found to fit a one-compartment open model with first-order absorption in the two groups of pigs. Significant changes were not observed between healthy and diseased pigs in following parameters: A, Ka, Ke and Tmax. However, in diseased pigs, significant increases (P less than 0.01) were found in Vd and ClB, and significant decreases (P less than 0.01) in Cmax and AUC occurred. The increased body clearance (ClB) and greater apparent volume of distribution (Vd) of penicillin G could partly explain why the serum values of the drug were much lower in diseased pigs than in healthy pigs.

Interspecies Mixed-Effect Pharmacokinetic Modeling of Penicillin G in Cattle and Swine

“…Sparse data consisted mainly of the concentrations of penicillin G tissue residues, which were determined at least 1 h after the drug administration. In previous studies, the PK profile of penicillin G was described by a one-or two-compartment open model (54,62). Given that previous sampling periods were relatively short, a three-compartment open model was applied in our study in order to account for the slower terminal depletion phase of the later time-concentration data profile.…”