Related Experiment Video
Updated: Mar 10, 2026
Use of Rabbit Eyes in Pharmacokinetic Studies of Intraocular Drugs
Published on: July 23, 2016
Endophthalmitis Prophylaxis Using a Single Drop of Thermoresponsive Controlled-Release Microspheres Loaded with
Alex Mammen1, Eric G Romanowski1, Morgan V Fedorchak1
1University of Pittsburgh Medical Center (UPMC), The Charles T. Campbell Eye Microbiology Laboratory, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Purpose:
Postsurgical endophthalmitis is a sight-threatening problem. We introduce a simple approach by using a single application of thermoresponsive controlled-release microspheres, loaded with moxifloxacin, to prevent bacterial endophthalmitis in a rabbit endophthalmitis prevention model.
Methods:
We separated 24 rabbits into 3 treatment groups in which topical drop treatment was placed onto the conjunctival cul-de-sac: (1) a single drop of controlled-release microspheres containing moxifloxacin, (2) a single drop of controlled-release microspheres without moxifloxacin, and (3) multiple topical treatment with moxifloxacin alone every 15 minutes for 1 hour. All rabbits were challenged, 1 hour after microspheres drop placement and immediately after the fifth topical dose of moxifloxacin, with anterior chamber injections of Staphylococcus aureus. Rabbits in the topical moxifloxacin group also were treated after challenge and four additional times over the next 24 hours. After 24 hours, the rabbits were clinically evaluated for endophthalmitis and the animals were euthanized to culture for intraocular S. aureus. The treatment groups were compared statistically for bacterial endophthalmitis.
Results:
No eyes had endophthalmitis, based on clinical presentation and/or positive culture, in the groups with controlled-release microspheres loaded with moxifloxacin (0/8, 0%) or multiple drops of topical moxifloxacin (0/8, 0%). In contrast, 8 of 8 eyes (100%; P = 0.0001), had endophthalmitis among eyes treated with controlled-release microspheres drops without moxifloxacin.
Conclusion:
A single drop of controlled-release microspheres loaded with moxifloxacin was successful in preventing endophthalmitis. Further clinical studies will be required to confirm the full potential of controlled-release anti-infective loaded microspheres to prevent endophthalmitis.
Translational Relevance:
This study presents a simple method of prophylaxis to prevent postsurgical endophthalmitis.
Insights
A single application of moxifloxacin-loaded microspheres effectively prevented bacterial endophthalmitis in rabbits. This novel approach offers a promising, simple prophylaxis against postsurgical infections.
Area of Science:
- Ophthalmology
- Infectious Diseases
- Biomaterials Science
Background:
- Postsurgical endophthalmitis is a severe complication that can lead to vision loss.
- Current prophylactic methods may require frequent administration.
- Developing sustained-release antimicrobial delivery systems is crucial for preventing ocular infections.
Purpose of the Study:
- To evaluate the efficacy of a single application of thermoresponsive controlled-release moxifloxacin microspheres in preventing bacterial endophthalmitis.
- To compare this novel delivery system with multiple topical drops of moxifloxacin and a placebo microsphere formulation.
- To establish a rabbit model for assessing endophthalmitis prevention strategies.
Main Methods:
- Twenty-four rabbits were divided into three groups: moxifloxacin microspheres, placebo microspheres, and multiple topical moxifloxacin drops.
- Bacterial endophthalmitis was induced using Staphylococcus aureus anterior chamber injections one hour after microsphere administration or the final topical dose.
- Clinical evaluation and intraocular bacterial cultures were performed 24 hours post-infection to assess for endophthalmitis.
Main Results:
- No cases of endophthalmitis were observed in rabbits treated with moxifloxacin-loaded microspheres (0/8).
- The multiple topical moxifloxacin group also showed complete prevention of endophthalmitis (0/8).
- In contrast, all rabbits treated with placebo microspheres developed endophthalmitis (8/8, P = 0.0001).
Conclusions:
- A single application of moxifloxacin-loaded controlled-release microspheres is a highly effective method for preventing bacterial endophthalmitis.
- This approach represents a simple and potentially superior prophylactic strategy compared to conventional multi-dose topical treatments.
- Further clinical investigation is warranted to explore the full therapeutic potential of controlled-release anti-infective microspheres in preventing postsurgical endophthalmitis.
