Human vitreous levels of cefamandole and moxalactam

We gave 2-g intravenous doses of either cefamandole or moxalactam to 22 patients before vitrectomy. At 1 1 2 to 2 1 2 hours after administration, cefamandole vitreous concentrations varied from 0.36 to 2.05 μg/ml (mean, 0.94 μg/ml). Individual levels above the minimum inhibitory concentration of cefamandole for 90% (MIC₉₀) of Staphylococcus aureus were found in five of 11 patients. Levels above the MIC₉₀ for S. epidermidis were found in only two of 11 samples. Vitreous concentrations above the MIC₉₀ of cefamandole for common gram-negative pathogens were found in only two patients. Moxalactam concentrations in the vitreous varied from 1.1 to 4 μg/ml 30 minutes to six hours after administration. These levels were not above moxalactam's MIC₉₀ for S. aureus or S. epidermidis but were many times higher than the MIC9o of moxalactam for Enterobacteriaceae excluding Pseudomonas.