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Injectable microspheres with controlled drug release for glaucoma filtering surgery
H Kimura1, Y Ogura, T Moritera
1Department of Ophthalmology, Faculty of Medicine, Kyoto University, Japan.
Abstract:
The authors evaluated the effects of biodegradable poly (lactic acid) microspheres that provided the controlled release of the antimetabolic agent adriamycin (ADR) to prevent post surgical fibrosis after glaucoma filtering surgery. Fifty six eyes of 28 rabbits underwent posterior lip sclerotomy and received a 0.2 ml subconjunctival injection that contained microspheres 90 degrees from the filtering site immediately after surgery. Microspheres containing ADR (100 or 200 micrograms) were randomly administered to one eye. The fellow eyes served as controls and received microspheres without the drug. Intraocular pressure in the eyes treated with the microspheres that contained the drug was significantly lower than that in the control eyes from days 7-12 in the 100 micrograms group and from days 6-16 in the 200 micrograms group (P < .05). Eyes that received ADR had a significantly longer patent filtering bleb compared with the control eyes (P < .05). No corneal complications were observed in the eyes treated with 100 micrograms of ADR and the control eyes. Peripheral corneal opacities (25%) and epithelial erosion (17%) were observed in the eyes that received the 200 micrograms dose, but the cornea returned to normal after 4 wk. These results suggest that controlled-drug-release microspheres with an antimetabolic agent may be promising for preventing fibrosis after surgery.
Insights
Biodegradable microspheres releasing adriamycin (ADR) effectively reduced post-surgical fibrosis and maintained filtering bleb patency in glaucoma surgery models. Lower ADR doses showed fewer corneal complications, suggesting a promising approach for preventing ocular fibrosis.
Area of Science:
- Ophthalmology
- Biomaterials Science
- Pharmacology
Background:
- Post-surgical fibrosis is a common complication after glaucoma filtering surgery, potentially leading to bleb failure.
- Controlled drug delivery systems aim to improve therapeutic outcomes and minimize side effects.
Purpose of the Study:
- To evaluate the efficacy of biodegradable poly(lactic acid) microspheres for controlled release of adriamycin (ADR) in preventing post-surgical fibrosis.
- To assess the impact of ADR-loaded microspheres on intraocular pressure and filtering bleb patency.
Main Methods:
- A rabbit model of glaucoma filtering surgery (posterior lip sclerotomy) was used.
- Subconjunctival injections of adriamycin (ADR)-loaded microspheres (100 or 200 micrograms) or control microspheres were administered immediately post-surgery.
- Intraocular pressure, filtering bleb patency, and corneal complications were monitored.
Main Results:
- ADR-loaded microspheres significantly reduced intraocular pressure and prolonged filtering bleb patency compared to controls.
- The 100 microgram ADR dose showed no corneal complications, while the 200 microgram dose caused transient peripheral corneal opacities and epithelial erosion.
- Corneal issues resolved within 4 weeks in the higher dose group.
Conclusions:
- Controlled release of adriamycin via biodegradable microspheres is a promising strategy for preventing fibrosis after glaucoma surgery.
- Optimizing ADR dosage is crucial to balance antifibrotic efficacy with ocular surface safety.