Comparative penetration of moxifloxacin and gatifloxacin in rabbit aqueous humor after topical dosing.
OBJECTIVE
To evaluate the aqueous penetration of the fourth-generation fluoroquinolones moxifloxacin and gatifloxacin.


METHODS
University of Arizona, Tucson, Arizona, USA.


METHODS
Forty eyes of 20 New Zealand white rabbits were divided into 2 experimental groups. In Experiment I rabbits (20 eyes), a commercial preparation of topical gatifloxacin 0.3% was administered to 9 eyes and moxifloxacin 0.5% to 9 eyes; 2 eyes served as a control. Eyes were dosed according to a keratitis protocol; ie, every 15 minutes for 4 hours. The aqueous humor was sampled 10 minutes after the last dose. Experiment II rabbits (20 eyes) were dosed according to a cataract prophylaxis protocol; ie, 4 times a day for 10 days. The aqueous humor was sampled 1 hour after the last dose of antibiotic in 12 eyes and 24 hours after the last dose in 8 eyes. High-performance liquid chromatography was used to determine the fluoroquinolone concentration.


RESULTS
In the keratitis dosing protocol, the mean concentration of moxifloxacin in the aqueous (n=9) was 11.057 microg/mL (range 7.66 to 18.87 microg/mL), which was significantly higher than the mean concentration of gatifloxacin (n=8) (7.570 microg/mL [range 4.75 to 10.86 microg/mL]) (P=.030). In the cataract prophylaxis dosing protocol, the mean aqueous concentration of moxifloxacin (n=6) was 1.745 microg/mL (range 0.92 to 3.87 mg/mL). The mean concentration of gatifloxacin (n=6) was 1.207 microg/mL (range 0.44 to 2.44 microg/mL). The difference was not statistically significant (P=.359).


CONCLUSIONS
Higher mean levels (x1.46) of aqueous penetration were achieved with moxifloxacin than with gatifloxacin in the keratitis-dosing model. There was no statistically significant difference between the 2 drugs in the cataract prophylaxis dosing model. Both antibiotics had aqueous levels in excess of the minimum inhibitory concentration for most pathogenic organisms in both models.
University of Arizona, Department of Ophthalmology, Tucson, AZ, USA.
Jason M
JM
Levine
Robert J
RJ
Noecker
Lisa C
LC
Lane
Lisa
L
Herrygers
David
D
Nix
Robert W
RW
Snyder
D000287:Administration, Topical; D000818:Animals; D000890:Anti-Infective Agents / Q000493:pharmacokinetics*; D001082:Aqueous Humor / Q000378:metabolism*; D001372:Aza Compounds / Q000493:pharmacokinetics*; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D003315:Cornea / Q000378:metabolism; D024841:Fluoroquinolones / Q000493:pharmacokinetics*; D000077734:Gatifloxacin; D000077266:Moxifloxacin; D009883:Ophthalmic Solutions; D011804:Quinolines / Q000493:pharmacokinetics*; D011817:Rabbits
D000890:Anti-Infective Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D009883:Ophthalmic Solutions; D011804:Quinolines; D000077734:Gatifloxacin; D000077266:Moxifloxacin