[Anti-infectious effect of sustained antravitreal amphotericin B drug delivery system on experimental rabbit fungal endophthalmitis of Candida albicans].

Objective: To evaluate the efficacy and toxicity of sustained intravitreal amphotericin B drug delivery system (DDS) on experimental rabbit fungal endophthalmitis of Candida albicans.

Methods: Fifty New Zealand rabbits received central vitrectomy were followed by Candida albicans suspension (10(4) colony forming unit, cfu) injection. Rabbits were grouped randomly into five with ten in each as follows: Group A, endophthalmitis control group; Group B, DDS of vehicle alone; Group C, topical treatment with amphotericin B eyedrop; Group D, 5 microg of amphotericin B intravitreal injection every week for two weeks; Group E, DDS contained 1 mg of amphotericin B. Slit-lamp and indirect-ophthalmoscope were performed at different time for two months and vitreous opacity was compared between each group. The intraocular drug concentration was measured with high performance liquid chromatography (HPLC). Light and electron microscope were conducted to evaluate the toxicity of DDS and the effect of vehicle on intraocular structure. Electroretinography (ERG) was employed to evaluate the function of retina before and after the implantation of DDS.

Results: Endophthalmitis was obviously inhibited in group E while vitreous was still opacity in other groups. The drug concentration in vitreous cavity was stable and remained for two months in group E while rapidly went down two weeks later in group D. No toxic evidence was found in ocular, liver and kidney tissue and retinal ultrastructure was normal. There was no difference in ERG study before and after the DDS was implanted.

Conclusions: Sustained intravitreal amphotericin B DDS can significantly suppress the formation of fungal colony and inhibit the development of infection with long and stable intraocular drug concentration maintenance. The vehicle and amphotericin B DDS are safe to intraocular structure.