Corneal penetration of topical fluoroquinolones: Aqueous humour concentrations after application of levofloxacin 0.5% and ofloxacin 0.3% eye drops
Sven C. Kulus1, Markus Roessler1, Auli
Ropo2, Klaus Geldsetzer3
1Hochkreuzklinik Eye Hospital, Bonn, Germany,
2Santen Oy, Clinical Research, Helsinki, Finland,
3Santen GmbH, Germering, Germany
Summary: Purpose: To investigate the penetration of topically applied levofloxacin 0.5% and ofloxacin 0.3% eye drops into the aqueous humour of patients undergoing cataract surgery. Methods: In this randomized, investigator-masked study, 69 patients received four drops of either levofloxacin 0.5% or ofloxacin 0.3% eye drops within one hour (at 60 min, 45 min, 30 min and 15 min) prior to elective cataract surgery. Aqueous humour samples of at least 50?l were drawn from the anterior chamber at the beginning of the cataract operation. Fluoroquinolones concentrations in anterior chambers were measured using high performance liquid chromatography (HPLC). In order to exclude a dilution effect of the anterior chamber (AC), they were related to the AC volumes (measured by 3D-modelling of central Orbscan slit image photos) and AC depths (measured by ultrasound). Results: The mean concentration of levofloxacin (1139.9 ng/ml, SD 717.1) in the aqueous humour was significantly higher (p=0.0008) than that of ofloxacin (621.7 ng/ml , SD 368.7). The aqueous humour concentrations correlated negatively with the measured volumes and anterior chambers depths. Conclusions: The new fluoroquinolone, levofloxacin, is better soluble in water enabling the use of higher drug concentrations (0.5%) compared to other currently available fluoroquinolone eye drops (0.3%). This study shows that the concentration reached in the anterior chamber with levofloxacin eyedrops is about 2-fold higher when compared to that reached with ofloxacin eye drops. The concentration of the antibacterial isomer is approximately 3.5 to 4 times higher when levofloxacin is administered, assuming negligible stereo-selective uptake.