Abstract
Pharmacodynamic parameters and bactericidal activity against Streptococcus pneumoniae were investigated by simulating total and free serum concentrations of cefpodoxime versus cefditoren. Total drug T>MIC against the penicillin-intermediate (PISP) and resistant (PRSP) strains were 70.6% and 42.9% for cefpodoxime, and 89.6% and 62.5% for cefditoren, respectively. Comparing activity of free versus total cefpodoxime, there were reductions of 8.5% and 19.1% in T>MIC, related to bactericidal activity reductions from approximately 4.5 to 3 log10, and from 3 to 2.5 log10 against PISP and PRSP, respectively, at 10-12h. For cefditoren, reductions of 45.4% and 100% in T>MIC, were related to bactericidal activity reductions from approximately 5.5 to 2-2.5 log10 and from approximately 2.5 to 1.5 log10 against PISP and PRSP, respectively, at 10-12h. Higher differences in activity were found against the less resistant strains when comparing total versus free-drug profile.