Related Experiment Videos
Continuous flow contact lens delivery of gentamicin to rabbit cornea and aqueous humor
D S Rootman1, R P Willoughby, R Bindlish
1Department of Ophthalmology, University of Toronto, Ontario, Canada.
Abstract:
The Morgan Therapeutic Lens (MTL) was investigated as a continuous corneal perfusion system in New Zealand white rabbits. Gentamicin concentration in the cornea and aqueous humor delivered by the MTL was compared to gentamicin drops (13.6 mg/ml) administered every 15 or 30 minutes. Gentamicin (1 mg/ml) or 5 mg/ml was perfused at 10 ml/hr for up to 4.0 hours. At each time interval of 0.5, 1, 2 and 4 hours, homogenized corneas and aqueous humour were assayed for gentamicin concentrations. The highest aqueous humour gentamicin concentrations of 57.99 +/- 12.86 micrograms/ml were significantly higher with the MTL and 5 mg/ml of gentamicin compared with the MTL and 1 mg/ml of gentamicin or than drops applied every 30 minutes, but not significantly different than drops every 15 minutes. Highest corneal concentrations of gentamicin of 496.04 +/- 101.16 micrograms/gm cornea were significantly higher with MTL and 5 mg/ml of gentamicin compared with the MTL and 1 mg/ml gentamicin or than drops applied every 30 minutes, but not significantly different than drops every 15 minutes. All mean gentamicin concentrations attained via the MTL exceeded the mean inhibitory concentration for most sensitive bacterial species. The MTL is a reliable drug delivery system with distinct advantages, and may be a useful therapeutic modality in the ocular delivery of gentamicin and other drugs.
Insights
The Morgan Therapeutic Lens (MTL) offers effective ocular gentamicin delivery, achieving high concentrations in rabbit corneas and aqueous humor. This continuous perfusion system shows promise for treating eye infections.
Area of Science:
- Ophthalmology
- Pharmacology
- Drug Delivery Systems
Background:
- Bacterial keratitis and endophthalmitis require effective antibiotic delivery to ocular tissues.
- Conventional topical antibiotic drops may have limitations in achieving therapeutic concentrations in the cornea and aqueous humor.
- Continuous drug delivery systems are being explored to improve ocular drug penetration.
Purpose of the Study:
- To evaluate the Morgan Therapeutic Lens (MTL) as a continuous corneal perfusion system for gentamicin delivery.
- To compare gentamicin concentrations in the cornea and aqueous humor achieved by the MTL versus conventional eye drops.
- To determine the efficacy of the MTL in achieving concentrations above the minimum inhibitory concentration for common bacterial pathogens.
Main Methods:
- The MTL system was used to perfuse gentamicin (1 mg/ml or 5 mg/ml) at 10 ml/hr for up to 4 hours in New Zealand white rabbits.
- Gentamicin concentrations were measured in homogenized corneas and aqueous humor at 0.5, 1, 2, and 4 hours.
- These concentrations were compared to those achieved with topical gentamicin drops (13.6 mg/ml) administered every 15 or 30 minutes.
Main Results:
- The MTL with 5 mg/ml gentamicin achieved significantly higher concentrations in both aqueous humor (57.99 +/- 12.86 µg/ml) and cornea (496.04 +/- 101.16 µg/gm) compared to 1 mg/ml or drops every 30 minutes.
- Corneal and aqueous humor gentamicin levels with the MTL (5 mg/ml) were comparable to drops administered every 15 minutes.
- All achieved gentamicin concentrations exceeded the minimum inhibitory concentration for most susceptible bacterial species.
Conclusions:
- The Morgan Therapeutic Lens is a reliable system for continuous ocular drug delivery.
- The MTL demonstrates potential as a valuable therapeutic modality for ocular gentamicin delivery, offering advantages over conventional methods.
- Further investigation into the MTL for delivering other ocular medications is warranted.