树枝化聚乳酸的合成及其载药微球制备的研究
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摘要
本文采用收敛法合成一种4代树枝状聚酯大分子,研究了基于此树枝状聚酯大分子的树枝化聚乳酸的合成及其载药微球的制备。该树枝化聚乳酸是一种中间为亲水性的PEG链段,两端为各有16个疏水性的PLLA链段的哑铃型三嵌段树枝化共聚物；其合成过程为：将氨基封端的树枝状聚酯大分子接到线性窄分布端羧基用N-羟基琥珀酰亚胺(NHS)活化的聚乙二醇(PEG)分子两端,脱除表面缩酮基保护后,以此为引发剂引发丙交酯开环聚合得到目标产物。通过红外光谱仪(FT-IR)、核磁共振波谱仪(NMR)、凝胶渗透色谱仪(GPC)、差示扫描量热仪(DSC)、热重分析仪(TG)等分析方法表征了树枝状聚酯大分子和树枝化共聚物。研究表明这种用该种方法合成的树枝状聚酯大分子结构明确,产物纯净；共聚物的玻璃化转变温度、熔点和结晶度都下降,亲水性得到提高；共聚物的PLLA链段可通过单体/引发剂的比例来调节,产物的分子量高并且分子量分布窄,分子表面有大量的活性端羟基可供化学修饰。将该共聚物用乳化溶剂挥发法制备成微球,用扫描电镜(SEM)、激光粒度仪(LS)等分析方法表征微球的形貌和粒径大小和分布,结果表明微球外形规整光滑,表面无空隙；微球平均粒径在1.40-3.17μm范围内,得到的微球粒径分布较为均一。制得的替莫唑胺-树枝化PLLA微球载药量可以达到20.1%,有一定的缓释效果,体外缓释时间为48h。
The synthesis of dendronized polylactide (PLLA) and preparation of its drug-loading microshpere which was based on the four-generation polyester dendrons synthesized by divergent method were investigated. The dendronized PLLA is a well-defined dumbbell-shaped tri-block copolymer, consisting of hydrophobic PLLA and hydrophilic linear poly(ethylene glycol) (PEG) with narrow molecular weight distributions and varied PLLA arm lengths, which have been synthesized via the sequential preparation of terminal dendronized polyhydric PEG and ring-opening polymerization of L-lactide (LA). The terminal dendronized polyhydric PEG was prepared by the conjugation of amine-terminated fourth-generation polyester dendrons with NHS-activated PEG followed by the deprotection of acetonide groups at the surface of the dendrons. The dendrons and productions were characterized by FT-IR, NMR, GPC, DSC and TG. It was discovered that the dendrons were well-defined and the PLLA arms can be readily controlled by the feed ratio of LA monomer to the hydroxyl groups in PEG macro-initiator. The copolymer's glass transition temperature, melting point and crystallinity were declined. And the copolymer has high molecular weight with narrow molecular weight distributions and improved hydrophilicity with much terminal hydroxyl which could be chemical modificated. The copolymer microsphere was prepared by emulsion-solvent evaporation method, characterized by SEM and SL, which showed a range of 1.40μm to 3.17μm in mean diameter with narrow microsphere size distribution and regular smooth surface without gap. The drug loading efficiency of temozolomide-dendronized polylactide microsphere is 20.1%and the in vitro control release time is 48 hours.
The synthesis of dendronized polylactide (PLLA) and preparation of its drug-loading microshpere which was based on the four-generation polyester dendrons synthesized by divergent method were investigated. The dendronized PLLA is a well-defined dumbbell-shaped tri-block copolymer, consisting of hydrophobic PLLA and hydrophilic linear poly(ethylene glycol) (PEG) with narrow molecular weight distributions and varied PLLA arm lengths, which have been synthesized via the sequential preparation of terminal dendronized polyhydric PEG and ring-opening polymerization of L-lactide (LA). The terminal dendronized polyhydric PEG was prepared by the conjugation of amine-terminated fourth-generation polyester dendrons with NHS-activated PEG followed by the deprotection of acetonide groups at the surface of the dendrons. The dendrons and productions were characterized by FT-IR, NMR, GPC, DSC and TG. It was discovered that the dendrons were well-defined and the PLLA arms can be readily controlled by the feed ratio of LA monomer to the hydroxyl groups in PEG macro-initiator. The copolymer's glass transition temperature, melting point and crystallinity were declined. And the copolymer has high molecular weight with narrow molecular weight distributions and improved hydrophilicity with much terminal hydroxyl which could be chemical modificated. The copolymer microsphere was prepared by emulsion-solvent evaporation method, characterized by SEM and SL, which showed a range of 1.40μm to 3.17μm in mean diameter with narrow microsphere size distribution and regular smooth surface without gap. The drug loading efficiency of temozolomide-dendronized polylactide microsphere is 20.1%and the in vitro control release time is 48 hours.
引文
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[2]Qing Cai, Youliang Zhao, Jianzhong Bei, Fu Xi, Shenguo Wang. Synthesis and Properties of Star-shaped Polylactide Attached to Poly(amidoamine) Dendrimer. Biomacrolecules.2003,4:828-834
[3]Willians DF. Definition in Biomaterials. New York:Elsevier Science Ltd.1987,7:66-72
[4]林思聪.高分子生物材料分子工程研究进展(上).高分子通报.1997,1：1-7
[5]Thull R. Physicochemical principles of tissue material interactions. Biomolecular Engineering.2002,19:43-50
[6]Joseph Jagur-Grodzinski. Polymers for tissue engineering, medical devices, and regenerative medicine. Concise general review of recent studies. Polymers for Advanced Technologies.2006,17(6):395-418
[7]James M, Anderson. Biological Response to Material. Annu Rev Mater Res.2001,31: 81-110
[8]Rafael Auras, Bruce Harte, Susan Selke. An Overview of Polylactides as Packaging Materials. Macromolecular Bioscience.2004,4(9):835-864
[9]Donald Garlotta. A Literature Review of Poly(Lactic Acid). Journal of Polymers and the Environment.2001,9(2):63-84
[10]Masanobu Ajioka, et al. Basic Properties of Polylactic Acid Produced by the Direct Condensation Polymerization of Lactic Acid. Bulletin of the Chemical Society of Japan. 1995,68(8):2125-2131
[11]Gruber, et al. Melt-stable lactide polymer composition and process for manufacture thereof. US [P]:5539081,1996
[12]Dobrzynski Piotr, Kasperczyk Janusz, Janeczek Henryk. et al. Synthesis of biodegradable glycolide/L-lactide copolymers using iron compounds as initiators. Polymer.2002,43(9):2595-2601
[13]Chen Depu, Sun Baoquan. New tissue engineering material copolymers of derivatives of cellulose and lactide:their synthesis and characterization. Materials Science and Engineering:C.2000,11(1):57-60
[14]Lemmouchi Y, Schacht E. Preparation and in vitro evaluation of biodegradable poly(e-caprolactone-co-D, L-lactide)(X-Y)devices containing trypanocidal drugs. Journal of Controlled Release.1997,45(3):227-233
[15]陈文娜,杨建,王身国等.聚丙交酯/聚乙二醇多嵌段共聚物的合成及其性能.高分子学报.2002,5：695-698
[16]陈红丽,贝建中,王身国.生物降解高分子-聚己内酯/聚氧乙烯/聚丙交酯三元共聚物水解行为的研究.高分子学报.2000,5：626-631
[17]E. Buhleier, W. Wehner, F. Vogtle, "Cascade" and "nonskidchain-like" syntheses of molecular cavity topologies. Synthesis.1978,16:155-158
[18]R. Esfand, D.A. Tomalia. Poly(amidoamine) (PAMAM) dendrimers:from biomimicry to drug delivery and biomedical applications. Drug Discov Today.2001,6:427-436
[19]Newkome GR, Yao ZQ, Baker GR, et al. Cascade molecules:a new approach to micelles arborol. Org Chem.1985,50:2003-2004
[20]Buhleier E, Wehner W, Vogtle F. Nonskid-Chain-Like Synthesis. Molecular Cavity.1978, 5:5-15
[21]Chen ZC, Cooper SL. Quaternary ammonium functionalized polypropylene. Polym Mater Sci Eng.1999,81:483-484
[22]Elizabeth R, Jean M, Frechet JMJ. Dendrimers and dendritic polymers in drug delivery. Drug Discovery Today.2005,10 (1):35-43
[23]Chen ZC, Cooper SL. Quaternary ammonium functionalized polypropylene. Polym Mater Sci Eng.1999,81:483-484
[24]Chen CZ, Beck-Tan NC, Cooper SL. Quaternary ammonium functionalized poly (propylene imine) dendrimers as effective antimicrobials:Structure-activity studies. Biomacromolecules.2000,1(3):473-480
[25]Liu L, Breslow R. A potent polymer/pyridoxamine enzymemimic. Am Chem Soc Commun.2002,124 (18):4978-4979
[26]Liu L, Breslow R. Dendrimeric pyridoxamine enzyme mimics. J Am Chem Soc.2003, 125:12110-12111
[27]Wu X, Huang S, Zhang J, et al. Preparation and characterization of novel physically cross-linked hydrogels composed of poly(vinyl alcohol) and amine-terminated polyamidoamine dendrimers. Macromol Biosci.2004,4:71-75
[28]Cai Q, Zhao Y, Bei J, et al. Synthesis and properties of star-shaped polylactide attached to poly(amidoamine) dendrimer. Biomacromolecules.2003,4:828-834
[29]Zhao Y, Shuai X, Chen C, et al. Synthesis and characterization of star-shaped Poly(L-lactide)s initiated with hydroxyl-terminated poly (amidoamine) (PAMAM-OH) Dendrimers. Chem Mater.2003,15:2836-2843
[30]Gillies ER, Frechet JMJ. Designing macromolecules for therapeutic applications: polyester dendrimers poly(ethylene oxide) "Bow-Tie" hybrids with tunable molecular weight and architecture. Am Chem Soc.2002,124:14137-14146
[31]Paleos CM, Tsiourvas D, Sideralou Z, et al. Acid-and salt-triggered Multifunctional poly(propylene imine) dendrimer as a prospective drug delivery system. Biomacromolecules.2004,5 (2):524-529
[32]马光辉,苏志国.高分子微球材料.北京化学工业出版社.2005,75-78
[33]方仕江,王凯,潘祖仁.乳液聚合瞬时乳胶粒大小和分布及其控制策略.合成树脂.]994,11(1)：3-5
[34]Hollis Q L. Separation of gaseous mixtures using porous polyaromatic beads. Anal Chem. 1996,38(2):309-316
[35]Iman M, Celebi S S, Ozdura A R. Preparation of photo oxidized magnetic polystyrene beads for enzymei mobilization. Reactive Polymers.1992,17:325-330
[36]冯连芳,高彦芳,王凯.用羟基碳酸钙聚乙烯醇复合分散剂进行苯乙烯悬浮聚合.合成橡胶工业.1992,15(6)：336-340
[37]方仕江,潘云,周其云.在无机分散剂存在下苯乙烯悬浮聚合宏观成粒的特征.化工学报.1993,44(6)：740-743
[38]余晓,赵睿.单分散非多孔交联聚甲基丙烯酸环氧丙酯微球作为亲和色谱载体的研究.分析化学.2005,33(5)：544-548
[39]冯连芳,高彦芳,王凯.用羟基碳酸钙聚乙烯醇复合分散剂进行苯乙烯悬浮聚合.合成橡胶工业.1992,15(6)：336-340
[40]SERGIO F, HANS P MERKLE, BRUNO G. Microencapsulation by solvent extraction/evaporation:reviewing the state of the art of microsphere preparation process technology. J Controlled Release.2005,102:313-33
[41]彭洪修,古宏晨,郑志风等.高分子微胶囊药物释放体系.化工新型材料.2000,28(12)：7-11
[42]SHUKLA A J, PRICE J C. Effect of drug particle size on the dissolution of the ophylline from microspheres made from low molecular weight cellulose acetate propionate. Pharm Res,1989,6(5):418-419
[43]RAGHAVENDRA C, MUNDARG I, SRIRANGARAJAN S, et al. Development and evaluation of novel biodegradable microspheres based on poly(D,L-lactide-co-glycolide) and poly(e-caprolactone) for controlled delivery of doxycycline in the treatment of human periodontal pocket:In vitro and in vivo studies. J Controlled Release.2007,119: 59-68
[44]LAGARCE F, GARCION E, FAISANT N, et al. Development and characterization of interleukin-18-loaded biodegradable microspheres. International Journal of Pharmaceutics.2006,14:79-88
[45]BAHRI Z E, TAVERDET J L. Elaboration and characterization of microparticles loaded by pesticide model. Powder Technology.2007,172:30-40
[46]CORTESIA R, ESPOSITOA E, LUCAB G, et al. Production of lipospheres as carriers for bioactive compounds. Biomaterials.2002,23:2283-2294
[47]李德冠,姜丹,姜云垒等.聚乳酸微球的制备.吉林大学学报,2005,43(6)：842-846
[48]ROJAS J, PINTO-ALPHANDARY H, LEO E, et al. A Polysorbate based non-ionic surfactant can modulate loding and release of B-lactoglobulin entrapped in multiphase poly(DL-lactide-co-glycolide) microspheres. Pharm Res.1996,16:255-260
[49]DE ROSA G, IOMMELLI R, LA ROTONDA M, et al. Influence of the co-encapsulation of different non-ionic surfactants on the properties of PLGA insulin-loded micospheres. J Controlled Release.2000,69:283-295
[50]ARSHADY R. Preparation of biodegradable micmspheres and microcapsules: polylactides and related polyesters. J Controlled Release.1991,17:1-22
[51]Lam M L, Duenas E T, Cleland J L. Encapsulation and stabilization of Nerve Growth Factor into poly(lactide-co-glycolic) acid microspheres. Pharm. Sci.2001,90: 1356-1365
[52]Witschi C, Doelker E. Influence of the microencapsulation method and peptide loading on poly(lactic acid) and poly(lactide-co-glycolide acid) degradation during in vitro testing. Controlled Release.1998,51:327-341
[53]Hejazi R et. al. Stomach-specific anti-H pylori therapy I:preparation and characterization of tetracycline-loaded chitosan microsphere. Pharm. Sci.2002,235:87-93
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