Abstract:

BACKGROUND: There are currently few studies regarding the pharmacokinetics of vancomycin via intravitreous injection.
OBJECTIVE: To determine the concentration of vancomycin injected into the vitreous chamber of conscious rabbits. 
METHODS: A microdialysis probe was implanted into vitreous chamber of normal rabbit eyes and rabbit eyes infected with bacterial endophthalmitis for 24 hours, and 10 g/L vancomycin 0.1 mL was administered intravitreally. The drug concentration in the vitreous chamber of rabbit eyes was determined at 0.5, 1, 2, 4, 6, 12, 24, 48, 72 and 84 hours after injection, through the microdialysis and high performance liquid chromatogram-ultraviolet detection.
RESULTS AND CONCLUSION: The metabolism of vancomycin showed an open two-compartment model in normal rabbit eyes. Its half-life was 51.66 hours and the peak concentration was 695.92 mg/L. The metabolism of vancomycin in the infected vitreous chamber showed a one-compartment model. Its half-life was 11.91 hours and the peak concentration was 713.35 mg/L. All rabbits were injected with drugs for 84 hours and the intravitreous concentration of vancomycin was higher than minimal inhibitory concentration. The experimental findings indicate that microdialysis coupled to high performance liquid chromatography is a powerful tool to investigate the ocular pharmacokinetics of vancomycin, and the samples are harvested in a real-time, continuous and dynamic fashion when the experimental animals are conscious.