Antibiotic levels in experimentally infected mice in relation to therapeutic effect and antibacterial activity in vitro

Abstract

Antibiotic levels in blood were determined in experimentally infected mice following administration of a number of different penicillins at the median protective dose (PD₅₀) and these levels were correlated with in vitro MIC determinations. When administered by repeated dosage the PD₅₀ values were found to be lower than when the antibiotics were administered as a single dose and for the majority of the antibiotics tested the resulting peak levels in blood were below the in vitro MIC value. The results are discussed in relation to the nature of the antibiotic, the type of infection and the dosage schedule used.