Concentration of ampicillin in the vitreous after cryocoagulation.

After transconjunctival cryocoagulation rabbits received 100 mg/kg ampicillin intravenously. At different times in serum, aqueous humor, and in vitreous the concentrations of ampicillin were determined by the agar diffusion method. During the first 90 min after injection the concentration of ampicillin in the vitreous of the treated eyes reached 1 microgram/ml. Up to 3 days after coagulation such high concentrations were found. Five and ten days after coagulation the concentration reached 0.48 microgram/ml (mean value). With progressive cicatrization of the cryospots less ampicillin was found in the vitreous. In the vitreous of the untreated control eyes only minimal or no ampicillin was found in all of our experiments.