Penetration of linezolid into the anterior chamber (aqueous humor) of the human eye after intravenous administration

We determined the linezolid concentrations in serum samples and aqueous humors (AHs) from 21 patients undergoing cataract extraction. Cataract removal was performed at various times (from 60 to 270 min) after the end of a 30-min infusion of 600 mg of linezolid. Serum samples were obtained 1 h after the end of linezolid administration to determine the maximum concentration of linezolid (C-max); AHs and a second serum sample were taken simultaneously during the operation, and the concentrations of linezolid in AH (C-AH) and serum (C-S) were determined. The mean C-AH 1 h after linezolid administration was 4.94 mug/ml, and the mean ratio of C-AH to C-S (R=C-AH/C-S) was 0.43. All patients had a C-AH of >2 mug/ml, which was higher than the MIC at which 90% of Staphylococcus epidermidis strains are inhibited.