目的:评价环孢霉素A（CyA）壳聚糖纳米微粒在兔眼玻璃体腔内的药物代谢动力学。 方法:取实验兔20只分别在植入药后1，2，3，5，7，9，11，14，21，28d，各取2只兔(含4眼)，抽取玻璃体用高效液相色谱法检测CyA的药物浓度。 结果:CyA壳聚糖纳米微粒在体外14d内药物累积释放比率为81％。在注入玻璃体腔内28d均可检测到CyA，11d时为最高浓度1237.7ng/mL，最小浓度在第28d测为4485ng/mL。 结论:CyA壳聚糖纳米微粒在玻璃体腔能缓慢释放CyA，有很高的生物利用度。壳聚糖纳米微粒有望成为一种新型的药物载体，用于治疗眼后节疾病。

AIM: To evaluate the pharmacokinetics of cyclosporine A(CyA)-loaded chitosan(CS) nanoparticles in rabbits after intravitreal injection. METHODS: Experimental study on pharmacokinetics of sustained release drug in vitreous. Twenty rabbits were intravitreally injected CyA-loaded CS nanoparticles. Liquid vitreous was aspirated at the time of 1 day, 2,3,5,7,9,11,14,21,28 days postoperatively for determination of CyA concentration by high-performance liquid chromatography. RESULTS: 81％ of CyA was released in vitro from CyA-loaded CS nanoparticles after 14 days. The level of CyA ranged from 448.5ng/mL to 1237.7ng/mL during 28 days in vitreous cavities. CONCLUSION: Intravitreal injection of CyA-loaded CS nanoparticles leads to a sustained release of CyA with a high bioavailability. CS nanoparticles is a potentially promising delivery system for the posterior segment diseases.