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Updated: Aug 13, 2026
Use of Rabbit Eyes in Pharmacokinetic Studies of Intraocular Drugs
Published on: July 23, 2016
Clearance of intravitreal moxifloxacin
Mohan N Iyer1, Feng He, Theodore G Wensel
1Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030, USA.
Purpose:
To study the clearance of moxifloxacin after intravitreal injection in rabbits.
Methods:
Intravitreal injections of 200 microg/0.1 mL of moxifloxacin were administered to rabbits. Four eyes per time point after injection (1 hour and 6, 12, 24, and 36 hours) and three eyes at 48 hours, respectively, were enucleated and immediately frozen and stored at -80 degrees C. Ocular dissection and isolation of frozen vitreous was performed. Vitreous samples were acquired at the various time intervals after injection. Antibiotic assays were performed with high performance liquid chromatography.
Results:
The concentration of intravitreal moxifloxacin showed an exponential decay with a half-life of 1.72 hours. The mean vitreous concentration was 120.49 +/- 49.23 microg/mL 1 hour after injection, and declined to 20.23 +/- 5.85 microg/mL at 6 hours and 1.06 +/- 0.81 microg/mL at 12 hours, respectively.
Conclusions:
The vitreous concentrations achieved were several orders of magnitude greater than the MIC90 of organisms commonly involved in bacterial endophthalmitis, and therapeutic levels were maintained at 12 hours in uninflamed, phakic rabbit eyes. The pharmacokinetic data suggest that intravitreal moxifloxacin may have a role in the treatment of bacterial endophthalmitis.
Insights
Intravitreal moxifloxacin demonstrated rapid clearance in rabbit eyes with a half-life of 1.72 hours. Therapeutic levels were maintained for 12 hours, suggesting potential for treating bacterial endophthalmitis.
Area of Science:
- Ophthalmology
- Pharmacokinetics
- Microbiology
Background:
- Bacterial endophthalmitis is a severe intraocular infection requiring prompt and effective treatment.
- Intravitreal antibiotics are a common approach for managing endophthalmitis.
- Moxifloxacin is a fluoroquinolone with broad-spectrum activity against common ocular pathogens.
Purpose of the Study:
- To determine the vitreous clearance and pharmacokinetic profile of moxifloxacin following intravitreal injection in a rabbit model.
- To assess the duration of therapeutic drug concentrations in the vitreous humor.
Main Methods:
- Intravitreal injections of moxifloxacin (200 microg/0.1 mL) were administered to rabbit eyes.
- Vitreous samples were collected at various time points post-injection (1, 6, 12, 24, 36, and 48 hours).
- Moxifloxacin concentrations in vitreous humor were quantified using high-performance liquid chromatography (HPLC).
Main Results:
- Moxifloxacin exhibited an exponential decay in vitreous concentration with a calculated half-life of 1.72 hours.
- Mean vitreous concentrations were 120.49 microg/mL at 1 hour, decreasing to 20.23 microg/mL at 6 hours and 1.06 microg/mL at 12 hours.
- Achieved concentrations significantly exceeded the MIC90 for common bacterial endophthalmitis pathogens.
Conclusions:
- Intravitreal moxifloxacin maintained therapeutic concentrations in rabbit vitreous for at least 12 hours post-injection.
- The pharmacokinetic profile supports the potential utility of intravitreal moxifloxacin in the treatment of bacterial endophthalmitis.
- Further clinical studies are warranted to confirm efficacy and safety in human patients.
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