【作者】 潘研；

【导师】 郑俊民；

【作者基本信息】 沈阳药科大学 ， 药物制剂， 2002， 硕士

【摘要】 本文主要研究了口服胰岛素纳米粒的处方、制备、性质、药效学、药动学、与皮下注射的相对药理生物利用度及对纳米粒进行表面修饰以提高该制剂生物利用度研究。 基于为提高大分子蛋白质类药物口服给药生物利用度的目的，本论文具体作了如下的研究工作。以生物相容性及可生物降解性的乳酸／羟基乙酸共聚物(PLGA)为载体材料，采用复乳-溶剂挥发法制备了胰岛素聚酯纳米粒(INS-PLGA-NPs)。以纳米粒对胰岛素的包封率为指标，采用正交设计法优化处方组成及工艺；透射电镜(TEM)及激光散射法(LD)观察了粒子的表面形态及测定了平均粒径与粒度分布。低温超速离心法分离了该纳米粒，高效液相色谱法测定了胰岛素的包封率，考察了该胶体分散系的放置稳定性。结果表明，复乳制备时，乳化剂的性质及浓度是影响制剂性质的一个重要因素。优化后的处方所制备的纳米粒，粒子形状规整，分布均匀，数均平均径为(149.5±38.1)nm，多分散系数为0.15，包封率为(43.5±0.6)％。该纳米粒胶体分散系于4℃，放置6个月后，无分层絮凝现象，粒子大小、形态及包封率无明显变化。 γ-射线放射免疫法考察了该纳米粒的载药形式；恒温振荡法对纳米粒体外释药行为及空白纳米粒体外降解特性进行了研究，初步探索了纳米粒的体外释药规律。结果表明该纳米粒吸附与包埋载药同时并存，粒径是影响载药方式的重要因素。纳米粒中胰岛素的释放存在较大的突释，之后为缓慢释放阶段，药物主要是通过聚合物骨架的扩散和降解而释放，而聚合物的降解对药物的释放起着主导作用，但聚合物降解十分缓慢，导致药物释放较为缓慢。 胰岛素纳米粒药效学研究结果表明：纳米粒不仅对正常大鼠有降血糖作用，而且对四氧嘧啶致糖尿病大鼠以及肾上腺素造成的高血糖小鼠也有降血糖作用，且降血糖水平与剂量之间存在一定的关系。灌胃4h后，有显著的降血糖作用，10h后血糖降至最低(P＜0.05)。当剂量是10U/kg时，血糖降低百分率可达(52.3±10.5)％，且低血糖持续达6h，与皮下注射胰岛素溶液相比，相沈阳药科大学硕士学位论文 摘 要对药理主物利用度为门03士06）％。利用“’1－胰岛素试剂色测得正常大鼠灌服胰岛素纳米粒胶体分散系后 sh，血清胰岛素浓度显著增加（＊P、005），证明确有外源性的胰岛素进入循环系统。以天然生物粘附性材料壳聚糖对该纳米粒包衣，制得壳聚糖包衣胰岛素纳米粒，糖尿病大鼠灌胃后，降血糖作用显著增强（”尸＜005），生物利用度提高到（154士0、8）％，明显高于未包衣普通纳米粒，证明了该修饰方法的有效性。 此外，为探索胰岛素纳米粒的粒度与药效的关系，制备了不同粒径的生物粘附性聚合物的载药纳米粒，考察了各类微粒的体内外行为，结果表明，粒度为（3忙土沁）一比门23士叩）一和门06土2m）一的胰岛素纳米粒具确更强的降血糖作用，提示：粒度不同的纳米粒对胰岛素胃肠道吸收有不同程度的促进作用。更多还原

【Abstract】 The main goal of this paper was to prepare insulin-loaded nanoparticles and to investigate the physico-chemical characteristics of them, drug efficacy in vivo, pharmacokinetics as well as pharmacological bioavailability relative to sc. On the basis of these knowledges, some measures were taken to increase the bioavailability of insulin formulations and the results were carried out to be promising.This paper included some works as following in order to increase the gastrointestinal absorption of insulin. Biodegradable and biocompatible copolymer poly(lactide-co-glycolide) acid (PLGA) used as a vehicle, insulin-loaded PLGA nanoparticles (INS-PLGA-NPs) were prepared by a multiple emulsion/solvent evaporation procedure. Orthogonal design experiments were performed to optimize the conditions for the process. The surface morphology and particle size distributions of the NPs were examined by transmission electron microscopy and laser diffraction, respectively. The entrapment efficiency was determined by HPLC after separating the NPs from the suspension under ultra centrifugation at 40 000rpm, 10 for 30min and the stability of the NPs suspension was investigated. The results showed that the NPs prepared in our experiment regular and well-distributed with a mean diameter of 149.5nm, a polydispersity index of 0.15 and an encapsulation efficiency up to (43.5 0.6)%, in addition, the nature and concentration of the emulsifier were two of the most important factors influencing on the characteristics of the NPs. Results of the stability experiments indicated that there weren’t any changes on the NPs suspension after they were stored at 4癈 for 6 months.The loading pattern of different sizes of NPs was assayed by radioimmunoassay (RIA). The release behavior and biodegradable characteristics of the NPs were studied in vitro to explore the mechanism of release property. Results showed that much of the insulin loaded was absorbed on the surface of the NPs and the particle size may be one of the mostimportant factors affecting the pattern of loading. The release behavior in vitro showed an initial burst effect followed by a slower rate stage. The slower release was resulted from insulin diffusion from the matrix and the degradation of the polymers, among which the latter had a significant influence on it. However, the slow degradation of the polymers led to sustained release of insulin from the NPs.The results of the drug efficacy in vivo showed that the NPs had hypoglycemic effect not only on normal rats, but also on alloxan-inducing diabetic rats and adrenaline-inducing hyperglycemic mice. Furthermore, the hypoglycemic effect had a relationship with the dosage of insulin in the PLGA-NPs. After oral administration, the plasma glucose level decreased significantly after 4h, 10h later the glucose level decreased to the lowest. When oral administration at a dosage of 10U/kg, the glucose level decreased nearly (52.3d: 10.5)% and the hypoglycemic state lasted for 6 h, the relative pharmacological bioavailability was calculated to be (10.3 0.6) %. The result of 125I-radioimmunoassay showed that the serum insulin level of normal rats increased apparently after 8h (*P<0.05). On the base of above experiments, chitosan, a natural bioadhesive polymer, was used as a surface modification material, chitosan-coated INS-PLGA-NPs were prepared. These NPs had a higher capacity of decreasing the glucose level than non-coated PLGA-NPs and the pharmacological bioavailability increased up to ( 15.4 0.8) %. It proved that the surface modification of bioadhesive polymers could enhance gastrointestinal absorption of insulin to a greater extent than non-coated NPs.Besides, in order to investigate the relationship between particle size and drug efficacy in vivo, different sizes of bioadhesive polymer particles containing insulin were prepared and their various properties were studied. The results showed that particle size of (345 60) nm in diameter led to a greater hypoglycemic effect on alloxan-inducing diabetic rats than (123 40)更多还原