Aqueous Humor Penetration Of Topically Applied Tobramycin And Ofloxacin

Local application of antibiotic eye drops ( such as fluoquinolones and amin-oglycoside) is frequently used to prevent and treat intraocular infections. The aim of this study was to compare the aqueous humor penetration of topically applied ofloxacin and tobramycin in human eyes.MethodsSenile cataract patients (104 eyes) receiving cataract extraction were randomized into three groups; Control, 24eyes; Ofloxacin, 40 eyes; Tobramycin, 40 eyes. Each group was randomized into two sub-groups, single dose mode: ofloxacin 0.3% eye drops or tobramycin 0. 3% eye drops was topically instilled one drop for once. Multiple dose mode: ofloxacin 0. 3% eye drops or tobramycin 0. 3% eye drops was topically instilled one drop every 15 minutes for six times. Aqueous samples were obtained from different sub-groups during surgery, 10, 20, 30, 60, 90 and 120min after the last drop, respectively. Concentration of the antimicrobial agents was determined by the HPLC ( High Performance Liquid Chromatography).ResultsSingle dose mode: Ofloxacin achieved relatively higher drug levels than to-bramycin in anterior aqueous humor, the peak concentration of ofloxacin and to-bramycin is at 30 ~ 60 and 30 minutes after administered, respectively. Multiple dose mode; The concentrations of ofloxacin are in a high level till 120 minutes after the last administered, conversely, the concentrations of tobramycin are too low to detected by the HPLC. Compare the concentrations to their MICgo, concentrations required for inhibition of 90% of pathogen strains in vitro, the concentrations of ofloxacin are higher than the MIC90 even 60min after the last administered in single dose mode and more than 120min in multiple dose mode, but in all eyes, the concentrations of tobramycin in the aqueous humor are lower than its MIC90.ConclusionsThe concentrations of ofloxacin and tobramycin in aqueous humor in multiple application groups were higher than that in single application groups. Ofloxacin achieved the higher aqueous humor concentration than tobramycin, it may be an useful ophthalmic agent for topical antibacterial management in preventing and treating endophthalmitis.