Aqueous humor penetration of gatifloxacin and moxifloxacin eyedrops given by different methods before cataract surgery

Purpose

To determine whether the penetration into the aqueous humor of 2 new fourth-generation fluoroquinolone antibiotics, gatifloxacin (Zymar) and moxifloxacin (Vigamox) eyedrops, was affected by different methods of administration before cataract surgery.

Setting

Pasqua Hospital, Regina, Saskatchewan, Canada.

Methods

This prospective randomized study comprised 193 patients. The patients were divided into 2 main groups. One group received gatifloxacin eyedrops and the other, moxifloxacin eyedrops. Each group was subdivided into 4 subgroups. All patients received the drops 4 times a day starting 2 days preoperatively. The first subgroup did not receive any more antibiotics. The second subgroup received the antibiotic drops 3 times, starting approximately 2 hours preoperatively. The third subgroup received a wick soaked in a dilating mixture containing the antibiotic. The fourth subgroup received the wick and the antibiotic drops at the time of preparation for surgery. At the beginning of surgery, 0.1 mL of aqueous humor was aspirated, frozen, and sent under ice by courier to the Provincial Laboratory for analysis by high-performance liquid chromatography.

Results

The study included 124 women and 69 men. The mean concentrations in the aqueous humor were 0.19, 0.82, 0.22, and 0.30 μg/mL in the 4 gatifloxacin subgroups, respectively, and 0.38, 2.16, 0.88, and 0.97 μg/mL in the 4 moxifloxacin subgroups, respectively. Analysis of variance showed the differences between the 2 antibiotics to be statistically significant.

Conclusions

Moxifloxacin penetrated the aqueous humor better than gatifloxacin regardless of the method of administration. Both antibiotics penetrated the aqueous humor well when given in drop form. They reached and exceeded the minimum inhibitory concentration levels for the most common ocular pathogens causing endophthalmitis. Only moxifloxacin reached these levels when the wick was used.