microbial inhibitional in non-inflamed human aqueous after oral antibiotic intake

purpose: to investigate the penetration of cefixime, cephalexin and ciprofloxacin into the human eye based on microbial inhibition by human aqueous samples after oral administration. method: sixty patients aged 40 to 75 years who were scheduled for cataract surgery were divided into three equal groups. one group received 500 mg oral ciprofloxacin 24, 12 and 2 hours preoperatively; another group received 500 mg oral cephalexin 24, 18, 12, 6 and 2 hours before the operation and the third group received 400 mg oral cefixime 24, 12 and 2 hours prior to surgery. immediately before opening the anterior chamber, 0.1 ml of aqueous was taped with an insulin syringe. a 4 ml sample of the patient’s blood was obtained simultaneously. aqueous and serum specimens as well as a standard antibiotic disc were placed on the culture media of a known bacterium which was completely sensitive to the respective antibiotic. after 48 hours microbial inhibition zone of each sample was compared to the standard antibiotic disc. result: no microbial inhibition zone was seen by aqueous samples, however very large zones of inhibition were seen by discs of serum samples and antibiotics. conclusion: it seems that oral cefixime, cephalexin and ciprofloxacin do not achieve effective concentrations in human aqueous for microbial inhibition.