苦参碱聚乳酸微球的缓释性和玻璃体腔注射的安全性研究

目的研究苦参碱聚乳酸微球（MAT-PLA-MS）的缓释性和玻璃体腔注射的安全性。方法透射电镜观察MAT—PLA—MS的形态，紫外分光光度法观测其体外释放情况。玻璃体腔彩色照相记录其分解过程，裂隙灯显微镜、间接检眼镜、视网膜电图（ERG）、光学显微镜和透射电镜观察不同剂量组的苦参碱游离药物和MAT—PLA—MS在注药后不同时间点对眼组织的影响。结果MAT—PLA—MS的平均粒径为2．28μm，载药量为6．17％。体外释放672h，累积释放百分率为87．93％，缓释作用明显。MAT—PLA—MS在玻璃体腔内随时间延长表现为逐渐降解的过程。游离药物各剂量组和载药微球各剂量组在玻璃体腔注射后各时间点裂隙灯显微镜和间接检眼镜检查均未见异常。游离药物4mg组注药后1dERGb波振幅下降。组织病理学检查表明，游离药物4mg组在注药后1d开始出现视网膜毒性反应，载药微球6mg组在注药7d后出现轻微的视网膜毒性反应。结论MAT—PLA—MS具有明显的缓释效果，安全剂量较游离药物大，有望成为一种理想的防治增生性玻璃体视网膜病变的给药系统。

Sustained release ability and safety of matrine polyactic acid microsphere intravitreal injection

Background The anti-proliferative effect of matrine has been demonstrated and its relevance to prevention and treatment of proliferative retinovitreopathy is concerned.Howeverthe intravitreous injection of free-matrine reiteratively may raise the risk of ocular infection.ObjectiveThe goal of the present study is to investigate the sustained releasing ability and safety of matrine polyactic acid microsphere(MAT-PLA-MS intravitreal injection.MethodsMAT-PLA-MS was prepared by Hebei Medical University and examined under the transmission electron microscope.The release of MAT-PLA-MS was monitored by ultraviolet spectrophotometry.Free-matrine with the dose of 1,2,4mg was intravitreally injected respectively in 12 eyes of New Zealand albino rabbits in free-matrine group and MAT-PLA-MS with matrine(2,4,6mg respectively was administered in 16 eyes separately in matrine microsphere group.The blank microsphere was injected in 6 right eyes as blank control group and normal saline solution was injected in 6 fellow eyes as control group.The retinal function change was evaluated by electroretinogram(ERG),and the morphological and histological change of retina following drug injection were assessed under the slit lamp biomicroscope,indirect ophthalmoscope,light microscope and transmission electron microscope.The decomposed process of MAT-PLA-MS in vitreous was recorded with ocular anterior segment and fundus color camera.Results MAT-PLA-MS containing matrine showed the spherical shape with the mean diameter of 2.28±47μm under the transmission electron microscope and the drug-loading rate 6.17% and drug-release rate 87.93% in vitro for 672 hours,presenting the controllable release characteristics.After implantation into the vitreous,the MAT-PLA-MS containing matrine decomposed gradually with the prolong of time.The b amplitudes of ERG maximum response were significantly declined in 4mg free-matrine injection group in comparison with before injection in various time points(P<0.01).However,no considerably differences were found in MAT-PLA-MS with matrine groups and control groups in various time points following the intravitreal injection(P>0.05).No obvious abnormal was seen under the slim lamp and ophthalmoscope through the study period.The changes of retinal ultrastructure were found from 1 through 28 days after injection of 4mg free-matrine,and slight retinal structural damage was seen from 7 through 28 days after injection of 6mg MAT-PLA-MS containing matrine.ConclusionThese results suggest that MAT-PLA-MS possesses good sustained release feature.MAT-PLA-MS containing matrine has less toxicity to retina than free-matrine after intravitreal injection.MAT-PLA-MS is an excellent drug delivery system.