玻璃体内注射载HIF-1α shRNA质粒的PLGA纳米粒眼部转染效率

目的观察携带载缺氧诱导因子-1α（HIF-1α）短发卡式小干扰RNA（shRNA）质粒（pshHIF-1α）的纳米粒转染眼部组织的可行性。方法应用聚乳酸聚乙醇酸共聚物（PLGA）包载绿色荧光蛋白（GFP）表达的pshHIF-1α,制备纳米粒,检测其粒径、包封率、载药量及体外释放情况;将48只大鼠分为4组,每组12只（12只眼）,分别向玻璃体内注入10μL磷酸盐缓冲液（PBS）、空白纳米粒（1.89mg/mL）、裸质粒pshHIF-1α（0.02mg/mL）和pshHIF-1α纳米粒（1.89mg/mL）。分别在注药后3、7、14、28d观察纳米粒的眼内穿透性和基因转染情况。通过组织病理学检查,观察注射后第3天眼内组织结构的改变。结果纳米粒的载药率和包封率分别为1.06%和60.2%,平均粒径为284nm,体外释药达4周。体内实验显示,载pshHIF-1α纳米粒定向聚集于视网膜色素上皮（RPE）层,GFP表达时间持续达28d。组织病理学检查眼内未见明显炎性细胞浸润。结论纳米粒可向眼底递送质粒形式的DNA,是眼部基因治疗安全、有效的载体之一。     

生物降解性阿霉素聚乳酸微球体外释放及对视网膜毒性的研究

研究生物降解性阿霉素聚乳酸微球的体外释放及其对视网膜的毒性。方法：采用溶媒挥发法制备生物降解性阿霉素聚乳酸微球。用扫描电镜观察其形态,荧光分光光度法观测其体外释放情况;28只兔用于间接检眼镜、ERG、光镜和透射电镜检查以评价药物的视网膜毒性。结果:制得的微球平均粒径为37.9μm,其中阿霉素载药量为2.85％;体外释放速率缓慢,第42天时阿霉素的释放率仅达66.44％;观察表明,游离阿霉素 剂量超过5μg或阿霉素聚乳酸微球超过15μg时,视网膜出现毒性反应。结论：阿霉素聚乳酸微球较游离阿霉素毒性小,具有缓释长效的特点,提示该制剂有可能成为一种有效的治疗增生性玻璃体视网膜病变的眼内释药系统。     

地塞米松-聚乳酸-羟基乙酸纳米粒玻璃体内注射对激光诱导的大鼠脉络膜新生血管的抑制作用

目的观察生物降解性多聚体材料聚乳酸-羟基乙酸(PLGA)包载的醋酸地塞米松(DA)(DA-PLGA)纳米粒玻璃体内注射对实验性脉络膜新生血管(CNV)的抑制效果,评价药物在玻璃体内的释药模式及其对视网膜的毒性反应。方法采用改良的乳化/溶剂蒸发法制备载药量为50%的DA-PLGA纳米粒。雄性BN大鼠54只,每只动物随机选取一只眼作为实验眼,采用激光光凝法建立CNV模型。随机分为DA-PLGA纳米粒组(24只)、DA组(24只)及生理盐水对照组(6只),分别给予实验眼玻璃体内注射DA-PLGA纳米粒10μl(含DA 100μg)、DA 10μl(含DA 100μg)及10μl生理盐水。于激光光凝后1、3、14、21、28、56 d,采用反相高效液相色谱法(RP-HPLC)检测大鼠实验眼玻璃体内DA药物浓度。激光光凝后14、56 d,通过荧光素眼底血管造影(FFA)观察CNV的生成率;之后处死动物,摘除眼球制作标本,进行光学显微镜和电子显微镜观察。结果DA-PLGA纳米粒在眼内释药模式呈4相,即初始突释、稳态释药、第三相突释和渐弱释药,持续释药时间近2个月。激光光凝后14 d,DA-PLGA纳米粒组、DA组和对照组CNV生成率分别为28.2%、31.6%和66.7%。经χ2检验,DA-PLGA纳米粒组和DA组CNV生成率较对照组明显降低(P<0.01)。激光光凝后56 d,光凝区纤维血管组织增生(FVP)的平均厚度在DA-PLGA纳米粒组、DA组和对照组中分别为(69.52±10.52)、(70.49±12.39)、(105.11±13.70)μm。经SNK-q检验,DA-PLGA纳米粒组和DA组FVP的厚度较对照组显著变薄(P<0.01)。激光光凝后14 d,透射电子显微镜检查发现,DA组节细胞层和神经纤维层的线粒体明显空泡化,内质网肿胀,高尔基复合体排列紊乱,微管及微丝排列紊乱。结论玻璃体内注射DA-PLGA纳米粒可以明显抑制实验性CNV的生长。与DA相比,DA-PLGA纳米粒具有药物毒性低、缓释及药效长久等特性。     

5-Fu纳米毫微粒的制备及体外对晶状体上皮细胞增生的抑制作用

目的制备5氟尿嘧啶(5fluorouracil,5Fu)聚乳酸纳米毫微粒并观察其表征及体外对兔晶状体上皮细胞的抑制作用。方法采用复乳法制备5Fu聚乳酸纳米毫微粒,观察毫微粒的大小、表面形态和结构,毫微粒载药率和体外药物释放曲线。取传3代晶状体上皮细胞进行对比试验,设5Fu纳米毫微粒、5Fu原药、空载纳米毫微粒组、空白对照组。设0.5～62.5mg·L-14个剂量组,作用24h、72h、120h、168h后光镜下观察细胞性状,MTT法检测抑制作用。结果(1)制备的5Fu纳米毫微粒平均粒径(191.000±0.202)nm;载药率为8.1%;首日药物突释率为38.3%,缓释时间20d;(2)5Fu纳米毫微粒和5Fu原药对兔晶状体上皮细胞均有抑制作用,并随时间和剂量的增加而增加。空载聚乳酸纳米毫微粒对细胞无抑制作用;(3)作用初期各剂量组5Fu纳米毫微粒的抑制作用低于或等于原药,随时间延长分别在不同时间点超过原药,差异有显著性。结论5Fu聚乳酸纳米毫微粒性状稳定,可长期释放药物,有效抑制兔晶状体上皮细胞的增生,随时间延长作用明显高于原药,可以作为靶向缓释药物载体。     

姜黄素纳米粒对人视网膜色素上皮细胞的示踪研究

目的:探讨脱氧胆酸基接枝的壳聚糖衍生物负载姜黄素纳米粒的合成方法及该药物纳米粒对人视网膜色素上皮(hRPE)细胞的作用。方法:合成姜黄素/壳聚糖-脱氧胆酸纳米粒并分析其性能。将负载荧光染料异硫氰酸荧光素的壳聚糖-脱氧胆酸及姜黄素/壳聚糖-脱氧胆酸作用于hRPE细胞24h后,于倒置荧光显微镜下观察避光培养1、3、5d后二者与hRPE细胞的相互关系。结果:通过将姜黄素与壳聚糖-脱氧胆酸混合制成负载药的壳聚糖衍生物纳米粒为淡黄色;药物从纳米粒中的释放在96h后达到平衡,累积释放药物量为31.6%。异硫氰酸/壳聚糖-脱氧胆酸与hRPE细胞作用1d后,壳聚糖-脱氧胆酸纳米粒大部分仍位于近细胞膜的部位;作用3d后,纳米粒逐渐向细胞核会聚,且大部分位于细胞核周围;作用5d后,可看到壳聚糖-脱氧胆酸纳米粒已进入细胞核,且纳米粒可能在细胞内溶酶体的作用下有部分降解。姜黄素/壳聚糖-脱氧胆酸纳米粒和hRPE细胞作用的关系与壳聚糖-脱氧胆酸大致相同。结论:通过壳聚糖-脱氧胆酸包载的姜黄素纳米粒能持续释放出姜黄素,具有较持久的缓释功能。     

叶酸靶向长春新碱纳米微球对腺样囊性癌细胞活性的影响

目的 制备连接有叶酸(folic acid,FA)的长春新碱(vinscristine,VCR)靶向缓释纳米微球(nanopaticles,NP)FA-PLGA(VCR)-NP,观察其表征及对体外培养的腺样囊性癌低转移株(adenoid cystic carcinoma,ACC-2)细胞增殖的抑制作用.方法 采用改良的复乳法制备FA-PLGA(VCR)-NP,测定NP的粒径分布、载药率及体外释放曲线等;MTT比色法检测高浓度下的PLGA-NP对肿瘤细胞的毒性作用,比较药物组VCR、PLGA(VCR)-NP、FA-PLGA(VCR)-NP 3种药物在不同浓度和不同作用时间对ACC-2细胞的抑制作用;异硫氰荧光素标记PLGA-NP和FA-PLGA-NP,荧光显微镜观察FA-PLGA-NP的靶向性及游离FA对其影响.结果 FA-PLGA(VCR)-NP形态圆整,大小均匀,平均粒径249.2nm,载药率4.5%,体外释放时间达14 d;PLGA-NP与ACC-2细胞共培养5 d,细胞存活率达80.0%以上;给药后第4～5天FA-PLGA(VCR)-NP对ACC-2细胞的抑制率显著高于VCR,3种药物对细胞抑制作用均呈时间和浓度依赖性;FA-PLGA-NP可靶向附着于ACC-2细胞表面,这种识别可以被FA竞争性抑制.结论 FA-PLGA(VCR)-NP具有稳定的栽药率和体外释放行为,具有良好的靶向识别力,体外实验证实具有优于VCR原药的抗肿瘤能力.     

地塞米松-PLGA纳米粒兔眼玻璃体内注射的药物代谢动力学

目的地塞米松(dexamethasone,DM)是眼科临床常用药物,但目前缺乏高效、低毒的给药途径。借助生物降解性多聚体材料聚乳酸-羟乙酸(PLGA)构建DM-PLGA纳米粒,兔眼玻璃体内注射可望在眼后节较长时间维持稳定的有效药物浓度。方法乳化/溶剂蒸发法制备载药量分别为20%和50%的DM-PLGA纳米粒,兔眼玻璃体内注射给药后于第1、7、14和21d分别进行临床观察和组织药物浓度的高效液相色谱分析。结果给药后21d内,角膜和房水中药物浓度均低于检测水平下限(10μg·L-1);血浆药物浓度最高为024mg·L-1;载药量20%和50%的2组中视网膜脉络膜药物浓度分别为011-0.42mg·L-1和0.38-0.88mg·L-1,玻璃体药物浓度分别为0.82-26.52mg·L-1和1.78-85.72mg·L-1。临床观察眼底未见异常。结论载药量50%组的DM-PLGA纳米粒在兔眼玻璃体内可维持药物浓度达3周,提示具有眼内注射应用的潜力。     

载汉防己甲素壳聚糖纳米微球的制备及其对人翼状胬肉细胞增殖的抑制作用

目的　通过制备新型载汉防己甲素的壳聚糖纳米微球,研究其对于人翼状胬肉细胞增殖的抑制作用。方法　化学合成新型壳聚糖衍生物 （deoxycholic acid-modified chitosan,DAMC）,与汉防己甲素作用合成载药纳米微球,并检测其性能。载药纳米微球作用体外培养的人翼状胬肉成纤维细胞第1天、3天、5天后,采用CCK-8法检测人翼状胬肉成纤维细胞的活性。结果　通过化学反应成功获得脱氧胆酸基团接枝的DAMC,可包载汉防己甲素药物,两者形成的载药纳米微球载药量较高,可高达76%。粒径50~500 nm,Zeta电位始终保持正电位。体外药物释放实验显示载药纳米微球缓释汉防己甲素可达48 h。细胞活性实验显示Tet组第1天、3天、5天细胞活性分别为（60.70±2.30）%、（50.22±2.35）%、（21.99±2.07）%,而Tet/DAMC组分别为（79.77±2.09）%、（63.24±2.83）%、（40.28±1.19）%,含10×10^-6 mol·L^-1汉防己甲素的载药纳米微球具有抑制人翼状胬肉成纤维细胞的作用,且细胞毒性较原药明显降低。结论　载药纳米微球具有缓释药物的作用,对人翼状胬肉成纤维细胞的增殖具有明显的抑制作用,且细胞毒性较原药明显降低,有望提高汉防己甲素防治翼状胬肉复发的效果。     

叶酸-磁双靶向多功能纳米分子探针用于视网膜母细胞瘤体外多模态成像的研究

目的：制备一种叶酸-磁双靶、载阿霉素(ADM)相变型脂质体纳米粒(FA-PFH-Fe₃O₄@ADM),观察其对视网膜母细胞瘤Y79细胞的寻靶能力及体外超声/光声/磁共振三模态成像能力。

方法：采用双乳化法制备FA-PFH-Fe₃O₄@ADM纳米粒,检测其基本特性及细胞安全性,观察纳米粒在808nm激光下的升温现象及相变情况。将对数生长期的Y79细胞进行分组,非靶向组及单磁靶组加入PFH-Fe₃O₄@ADM纳米粒(0.625mg/mL),单叶酸靶组及叶酸-磁双靶组加入FA-PFH-Fe₃O₄@ADM纳米粒(0.625mg/mL),并于单磁靶组和叶酸-磁双靶组的孔板侧放约4T磁铁1枚,评估纳米粒对Y79细胞的寻靶能力。此外,观察FA-PFH-Fe₃O₄@ADM纳米粒体外超声/光声/磁共振三模态成像能力。

结果：成功制备的FA-PFH-Fe₃O₄@ADM纳米粒呈分布均匀、大小均一的球形结构,平均粒径为338.6±2.20nm,成功装载ADM和Fe₃O₄,包封率分别为(41.76±4.12)%、(59.06±13.63)%,具有良好的顺磁性能,且对Y79细胞无明显的生物毒性。叶酸-磁双靶组吞噬率[(86.19±0.55)%]高于单叶酸靶[(43.36±5.91)%]和单磁靶组[(28.58±3.23)%](P<0.05)。激光作用下,FA-PFH-Fe₃O₄@ADM纳米粒能迅速升温并发生相变,且可以增强超声及光声成像,T₂模式下可对磁共振成像进行负性增强。

结论：本研究成功制备的FA-PFH-Fe₃O₄@ADM纳米粒不仅对视网膜母细胞瘤Y79细胞具有较好的靶向性,还能实现体外超声/光声/磁共振三模态成像。     

Sustained-release genistein from nanostructured lipid carrier suppresses human lens epithelial cell growth

AIM: To design and investigate the efficacy of a modified nanostructured lipid carrier loaded with genistein (Gen-NLC) to inhibit human lens epithelial cells (HLECs) proliferation. METHODS: Gen-NLC was made by melt emulsification method. The morphology, particle size (PS), zeta potentials (ZP), encapsulation efficiency (EE) and in vitro release were characterized. The inhibition effect of nanostructured lipid carrier (NLC), genistein (Gen) and Gen-NLC on HLECs proliferation was evaluated by cell counting kit-8 (CCK-8) assay, gene and protein expression of the proliferation marker Ki67 were evaluated with real-time quantitative polymerase chain reaction (RT-qPCR) and immunofluorescence analyses. RESULTS: The mean PS of Gen-NLC was 80.12±1.55 nm with a mean polydispersity index of 0.11±0.02. The mean ZP was -7.14±0.38 mV and the EE of Gen in the nanoparticles was 92.3%±0.73%. Transmission electron microscopy showed that Gen-NLC displayed spherical-shaped particles covered by an outer-layer structure. In vitro release experiments demonstrated a prolonged drug release for 72h. The CCK-8 assay results showed the NLC had no inhibitory effect on HLECs and Gen-NLC displayed a much more prominent inhibitory effect on cellular growth compared to Gen of the same concentration. The mRNA and protein expression of Ki67 in LECs decreased significantly in Gen-NLC group. CONCLUSION: Sustained drug release by Gen-NLCs may impede HLEC growth.     

Carboplatin- and Etoposide-Loaded Lactoferrin Protein Nanoparticles for Targeting Cancer Stem Cells in Retinoblastoma In Vitro

PurposeCancer stem cells (CSCs) are known to contribute to tumor relapses by virtue of their chemoresistance. With the knowledge that nanoformulations can overcome drug resistance, we evaluated the efficacy and cytotoxicity of clinical-grade carboplatin (CPT)– and etoposide (ETP)–loaded lactoferrin nanoparticles (Lf-Nps) on total, CD133-enriched (non-CSC), and CD133-depleted (CSC) populations of retinoblastoma (Rb) Y79 cells.MethodsPhysicochemical properties of drug-loaded Lf-Nps were measured with transmission electron microscopy and attenuated total reflectance–Fourier transform infrared. The encapsulation efficiency, uptake, and release of drug-loaded Lf-Nps were measured using high-performance liquid chromatography and a UV-visible spectrophotometer. Cytotoxicity of the standard and drug-loaded Lf-Nps was evaluated by the MTT assay.ResultsThe mean (SD) size and encapsulation efficiency of Lf-CPT and Lf-ETP were 61.2 (3.94) nm, 60% and 45.15 (5.85) nm, 38%, respectively, and the drug release efficiency was highest at pH 6. The increased drug uptake and lower release of drug-loaded Lf-Nps were observed in CSC and non-CSC populations compared to their standard forms. The relative increase of drug uptake and sustained intracellular retention of the drug-loaded Lf-Nps compared to standard drugs showed an enhanced cytotoxicity up to 50%, especially in Rb Y79 CSCs (IC₅₀: CPT, 230.3; Lf-CPT, 118.2; ETP, 198.1; and Lf-ETP, 129) compared to non-CSCs.ConclusionsOur study documents an increase in drug uptake, retention, and cytotoxicity of Lf-CPT and Lf-ETP on Y79 CSCs and non-CSCs as compared to their standard drugs in vitro. The reversal of chemoresistance in the CSC population by nanoformulation appears promising with the potential to pave the way for improved targeted therapy and better clinical outcomes.     

壳聚糖及其衍生物在眼科疾病中的应用与研究进展

壳聚糖作为甲壳素的脱乙酰化产物,是唯一的一种碱性阳离子多糖。因其具备良好的生物相容性、生物降解性、无毒和低致敏性使其在伤口愈合、药物载体、组织工程等生物医疗领域有着广泛的应用。本文结合壳聚糖及其衍生物的生物特性将其在眼表疾病的药物缓释(如在眼睑缺损、干眼、角膜炎、角膜伤口愈合、角膜组织工程方面的应用)、壳聚糖包裹的复合脂质体延缓白内障形成以及人工晶状体植入抗代谢物药物缓慢释放预防后发障、青光眼降眼压药物缓释与滤过性手术抗瘢痕化药物缓释、壳聚糖的水解产物壳寡糖治疗实验性自身免疫性前葡萄膜炎、视网膜病(胰岛素缓释治疗糖尿病视网膜病变、新型巩膜扣带材料治疗视网膜脱离、壳寡糖预防视网膜缺血再灌注损伤)等眼科各亚专业的应用与研究进展作一综述。但目前研究均较肤浅,多数属于体外或动物实验,尚缺乏设计严格的较大样本量的远期临床试验资料。     

Cyclosporine-loaded microspheres for treatment of uveitis: in vitro characterization and in vivo pharmacokinetic study

PURPOSE: A sustained intraocular level of immunosuppressive drug is desirable for the treatment of uveitis and other intraocular immune disorders. The objective of the present investigation was to assess the suitability of cyclosporine-loaded poly(lactic-co-glycolic acid) microspheres (CyS-PLGA-MS) to achieve this goal. METHODS: A solvent-evaporation method was used in the preparation of CyS-PLGA-MS. These microspheres were characterized for drug loading, entrapment efficiency, and in vitro release by high-performance liquid chromatography, particle size by phase-contrast light microscopy and surface morphology by scanning electron microscopy. The 3H-CyS-PLGA-MS suspension was injected into the vitreous body of healthy rabbits, and the concentration of cyclosporine in various ocular tissues and blood at predetermined intervals was measured by a scintillation counting technique and the pharmacokinetic parameters were calculated. Intravitreous administration of 3H-CyS solution was conducted as the control. RESULTS: The CyS-PLGA-MS was produced, with drug-loading ranging from 11% to 16% and a high entrapment efficiency from 86% to 98%. Microspheres were discrete, spherical particles with a diameter of approximately 50 microm. The CyS was constantly and slowly released from microspheres in the in vitro release experiment. Compared with CyS solution, microspheres prolonged the release of CyS and maintained therapeutic CyS concentrations for at least 65 days in disease-related tissues such as the choroid-retina and iris-ciliary body. The percentage of CyS released in vitro correlated well with the CyS distribution rate in vivo. CONCLUSIONS: CyS-PLGA-MS, displaying sustained intraocular release of CyS and showing advantages over CyS solution, may meet clinical needs more efficiently.     

Evaluations of therapeutic efficacy of intravitreal injected polylactic-glycolic acid microspheres loaded with triamcinolone acetonide on a rabbit model of uveitis

Conventional treatments of uveitis are not ideal because of the short period of therapeutic efficacy. In the present study, biodegradable polylactic-glycolic acid microspheres loaded with triamcinolone acetonide (TA) were prepared to achieve sustained drug release and their therapeutic efficacy was investigated on a rabbit model of uveitis. TA-loaded microspheres (TA-MS) were prepared by the solvent evaporation method and characterized for encapsulation efficiency, particle size, morphology and in vitro release. The therapeutic efficacy was studied on the rabbit experimental uveitis model based on scoring of the inflammation, aqueous leukocyte counting, aqueous protein determination and histological examination. The TA-MS exhibited smooth and intact surfaces with an average diameter of 50.87 μm. The drug-loading coefficient and encapsulation efficiency were 15.2 ± 0.6 % and 91.24 ± 3.77 %, respectively. The drug release from TA-MS lasted up to 87 days, but only 46 days for TA suspension. The change in surface morphology also showed sustained drug release from TA-MS. TA-MS exhibited improved therapeutic efficacy in lipopolysaccharide -induced uveitis compared to TA suspension, especially in regard to the inhibition of inflammation. The TA-MS had a longer-term therapeutic effect on intraocular inflammation in LPS-induced uveitis in rabbits compared to TA suspension. The results suggested that TA-MS can be developed as a potential sustained-release system for the treatment of uveitis.     

Subconjunctival nano- and microparticles sustain retinal delivery of budesonide,a corticosteroid capable of inhibiting VEGF expression

PURPOSE: The purpose of this study was to determine whether budesonide inhibits expression of vascular endothelial growth factor (VEGF) in a retinal pigment epithelial cell line (ARPE-19) and to determine whether subconjunctivally administered budesonide nano- and microparticles sustain retinal drug levels. METHODS: The effect of budesonide (100 pM to 10 microM) on VEGF secretion, expression of VEGF mRNA, and cytotoxicity were determined in ARPE-19 cells by ELISA, RT-PCR, and a cell-viability assay, respectively. To determine the involvement of glucocorticoid receptor in the observed effects of budesonide, secretion and mRNA expression studies were also performed in the presence of a glucocorticoid receptor antagonist (RU486). DL-Polylactide (PLA) nano- and microparticles containing budesonide were prepared by a solvent evaporation technique, and the particles were characterized for size, morphology, encapsulation efficiency, and in vitro release. Budesonide-PLA nano- and microparticles were administered subconjunctivally to one eye of Sprague-Dawley rats and drug levels in the retina, vitreous, lens, and cornea of both eyes were determined at the end of 1, 7, and 14 days. RESULTS: At concentrations devoid of cytotoxicity, budesonide inhibited VEGF secretion as well as mRNA expression in ARPE-19 cells in a dose-dependent manner. RU486 treatment prevented budesonide-mediated inhibition of VEGF secretion and VEGF mRNA expression. Budesonide-PLA nano- (345 nm) and microparticles (3.6 microm), with an encapsulation efficiency of 65% and 99%, respectively, sustained budesonide release in vitro. After subconjunctival administration, both budesonide-PLA nano- and microparticles produced sustained budesonide levels in the retina and other ocular tissues. CONCLUSIONS: Budesonide is capable of inhibiting VEGF expression through glucocorticoid receptor activity. Subconjunctivally administered budesonide-PLA nano- and microparticles sustain retinal drug delivery.     

Gantrez AN Nanoparticles for Ocular Delivery of Memantine: In vitro Release Evaluation in Albino Rabbits

Aim: To prepare and evaluate the in vitro release of memantine-loaded poly(anhydride) (Gantrez?) nanoparticles (NPs). The clinical safety and retinal toxicity caused by unloaded NPs after sub-Tenon and intravitreal ocular injections were also evaluated. Methods: Preparation and characterization of this type of NP as well as the in vitro release study are described. Twenty-three healthy New Zealand rabbits were used for clinical and histological assessment after sub-Tenon and intravitreal ocular injections of unloaded NPs. Results: The amount of drug associated with NPs was 55 μg of memantine/mg of NP. The release profile of memantine from this type of NPs was characterized by an initial burst effect, followed by continuous release of the drug for at least 15 days. No relevant complications were found during the clinical follow-up. The histological evaluation suggested that Gantrez NPs are well tolerated after sub-Tenon ocular injection and that signs of inflammation during the first days after intravitreal ocular injections can be considered a normal reaction of the eye's defence mechanism.     

环孢霉素A壳聚糖纳米微粒在兔眼玻璃体腔内药代动力学研究

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。     

Inhibitory efficacy of intravitreal dexamethasone acetate-loaded PLGA nanoparticles on choroidal neovascularization in a laser-induced rat model.

Purpose: The aims of this study were to investigate the inhibitory efficacy of intravitreal dexamethasone acetate (DA)-loaded by (D, L-lactide-co-glycolide) (PLGA) nanoparticles on choroidal neovascularization (CNV) in a laser-induced rat model and to evaluate its mode of drug release. Methods: DA loaded with PLGA nanoparticles containing 50% DA was prepared using an emulsification/solvent evaporation method. CNV was unilaterally induced by laser photocoagulation in rats. Different dosages of sterilized DA-loaded PLGA nanoparticles suspensions by intravitreal injection were evaluated (i.e., 50, 100, 200, and 400 mug) and the blank PLGA vehicle was the control. The concentration of DA in vitreous was measured by reverse-phase high-performance liquid chromatography (RP-HPLC). Flash electroretinography and transmission electron microscopy were performed to assess retinal toxicity. Fluorescein fundus angiography was performed to evaluate the incidence of CNV on days 14 and 56. The animals were sacrificed on day 56, then eyecups were processed for histologic analysis. Results: The in vitro release of DA from nanoparticles showed that 50% of the drug was released over 2 weeks and controlled release in a linear pattern for 40 days. The pharmacokinetics of DA-loaded PLGA nanoparticles in the eyes with CNV demonstrated a triphasic pattern. The DA concentrations in vitreous remained within the effective range, which is capable of inhibiting inflammatory responses for more than 56 days. On day 14 after photocoagulation, the incidence of CNV was 47.4% as for 50 microg, 28.2% for 100 microg, 15.8% for 200 microg and 7.9% for the 400 microg DA-loaded PLGA nanoparticles group, respectively, and 65.8% for the control. On day 56, The inhibition of DA-loaded PLGA nanoparticles on CNV showed a dose-dependent effect. No sign of retinal toxicity was detected. Conclusions: These results suggest that DA-loaded PLGA nanoparticles can dose-dependently inhibit the development of experimental CNV. The controlled intraocular delivery system of DA-loaded PLGA nanoparticles may be a potentiality for CNV treatment.