Half-life of intracameral gentamicin after phacoemulsification.

ABSTRACT

PURPOSE: To determine the half-life of intracameral gentamicin administered during phacoemulsification. SETTING: Southampton Eye Unit, Southampton General Hospital, England. METHODS: Thirty-one patients having scleral tunnel phacoemulsification were given intracameral gentamicin in the irrigation fluid. Samples of fluid were taken from the anterior chamber at the end of the operation and at various times postoperatively. The concentration of gentamicin in the samples was determined by fluorescence polarization immunoassay and the half-life calculated for a single compartment model using a peeling algorithm. RESULTS: The concentration of gentamicin in the anterior chamber after phacoemulsification decreased by half every 51 minutes (95% confidence interval, 42 to 66 minutes). CONCLUSION: Intracameral gentamicin was cleared from the anterior chamber after phacoemulsification at a rate that prevents the maintainance of the bactericidal levels required for reliable antibiotic prophylaxis.