Abstract
Purpose :
How to deliver the drug with therapeutic local concentrations to the area of infection remains a challenge, injections by needles repeatedly may increase the risks of intraocular infection and hemorrhage. This article compared the pharmacokinetics of demethylvancomycin in aqueous humors and vitreous after subconjunctival injection and Sub-tenon’s continuous infusion with a micro-infusion pump in a rabbit model, explores the alternative of using a Sub-tenon’s Continuous Micro-infusion for a long-term drug release in vivo.
Methods :
40 adult New Zealand white rabbit randomly divided into two groups. One group(N=20) received subconjunctival injection of demethylvancomycin (3 mg in 0.3 ml) in their right eyes, The other group(N=20) received the same concentration of demethylvancomycin at a 1ml/h infusion velocity continuous perfused into posterior sub-tenon in their right eyes.Four animals were killed at each designated time points (1 hour, 3 hours,6 hours,12 hours, and 24 hours ). The concentration of demethylvancomycin in the aqueous humor and vitreous were determined by high-performance liquid chromatography(HPLC).
Results :
The aqueous humor and vitreous regression equation is Y=122952X+173.846 (R2=0.9998, P<0.05). The subconjunctival injection group: demethylvancomycin concentration were(1.35±0.472)μg/ml,(0.477±0.271)μg/mL in aqueous and vitreous at 1 hour post-injection. Then the concentration achieve maximum at 3 hour post-injection and were (1.±4.427)μg/mL,(0.668±0.301)μg/mL. After that the concentration showed a declining trend. The continuous infusion group: demethylvancomycin concentration were(1.678±0.716)μg/ml,(0.328±0.139)μg/mLin aqueous and vitreous at 1 hour post-injection, then it achieve maximum at 3 hour post-injection and were (3.21±0.621)μg/mL,(2.31±1.632)μg/mL,then it decreased slightly and show a stable trend. No any ocular complication was found throughout the studying duration.
Conclusions :
In the subconjunctival injection group, the drug concentrations in vitreous body and aqueous humors were lower than minimal inhibitory contration (MIC) of the most gram-positive bacteria after 3hours. In the sub-tenon’s continuous micro-infusion group, the drug concentrations in vitreous body and aqueous was greater than the MIC for more than 24 hours.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.