Preparation methods and in vitro release of Resina Draconis-loaded biodegradable polymeric hollow nanoparticles

doi:10.3969/j.issn.2095-4344.2014.52.014

Abstract

Abstract:

BACKGROUND: As Resina Draconis is water insoluble, it is difficult to be made into injection. Meanwhile, the oral preparation and enemas of Resina Draconis, due to the water insolubility and large particle size, have poor in vivo absorption and very low bioavailability. Polymeric hollow nanoparticles have large surface area and strong adsorption characteristics; moreover, the hollow core parts can accommodate a large number of guest molecules. Therefore, the hollow nanoparticles have a series of peculiar properties based on the microcapsule effect.

OBJECTIVE: To review the literatures covering the preparation methods and in vitro release researches on Resina Draconis-loaded biodegradable polymeric hollow nanoparticles.

METHODS: A computer-based search was performed in PubMed database, Chinese Science and Technology Periodical Database (1989 to 2014), China Academic Conference Papers Database (1986 to 2014), Chinese Dissertations Database (1986 to 2014), China Patent Database (1985 to 2014), Chinese Science and Technology Paper and Citation Database (1999 to 2014), China Journal Full Text Database (1979 to 2014), China Outstanding Master's Degree Thesis Database (1999 to 2014), Chinese Doctoral Dissertations Full Text Database (1999 to 2014) for relevant articles by the retrieval key words of “resina draconis, nanoparticles, hollow particles, biodegradable polymer” in English and Chinese, respectively.

RESULTS AND CONCLUSION: The traditional Chinese medicine Resina Draconis is firstly dissolved in suitable solvents like ethanol, isopropanol or solvents, forming nearly saturated solution. Then the pre-made polymer hollow nanoparticles are dispersed in the solution, with ultrasonic oscillation for a certain time. After separation by high-speed centrifugation, Resina Draconis-loaded nanoparticles can be prepared successfully. It is of great importance to make the Chinese medicine Resina Draconis into microemulsion nanoparticles, forming “homogeneous solution” in the medium of water, which will lead to the remarkable improvement of the in vivo absorbability and bioavailability of Resina Draconis. Furthermore, the sustainable release of microemulsion contributes to little adverse reaction, low dosage, long duration, etc. Consequently, the Resina Draconis-loaded nanoparticle emulsion is expected to be made into powder, tablet, ointment, capsule, even injection or some other dosage forms. The nano-scale emulsion of Resina Draconis is expected to be injected intravenously, which will directly reach the focus through the blood circulation to cure blood stasis, cardiovascular and cerebrovascular diseases. In addition, the release rate of loaded drugs can be controlled by means of regulating the thickness and porosity of hollow nanoparticle shells, and by surface modification with biological chemicals, the drug-loaded nanoparticles are expected to possess targeting characteristics.

中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程

全文链接：

Key words: drugs, Chinese herbal, nanoparticles, review

CLC Number:

R318

Wang Xue-ming, Xing Chang-min, Li Nan. Preparation methods and in vitro release of Resina Draconis-loaded biodegradable polymeric hollow nanoparticles

[J]. Chinese Journal of Tissue Engineering Research, 2014, 18(52): 8438-8442.

Figures/Tables 2

2.1 高分子纳米空心粒子载体的制备目前制备高分子空心粒子的方法主要有乳液聚合法和模板法[26-27]。种子乳液聚合是目前为止研究最多、应用最广的制备核-壳/空心结构高分子复合粒子的方法，概括其基本工艺可以分为以下几步：首先采用乳液聚合的方法合成种子乳液，然后将第二单体加入到种子乳液中进行再聚合，即可获得具有核壳结构的聚合物乳液，最后用适当的溶剂除去核，得到空心粒子。模板法的关键在于模板，一般需要预先制得。模板在整个反应流程中不发生化学反应，聚合物在模板的表面形成并定型，因此模板的形状和尺寸直接决定所得空心球的形状和尺寸，通过调节模板的形貌达到调整微球形貌的目的。将微胶囊化的核-壳结构产物通过适当的方法去除模板核，得到空心粒子[28]。乳液聚合法和模板法制备高分子空心粒子各有所长，传统的乳液聚合以及种子聚合法制备高分子空心粒子具有体系组成复杂、粒径分布宽、产物结构不稳定等缺点；模板法具有形态可控的特点，但是通常反应条件苛刻，步骤繁琐，而且稳定性较差。文章提出一种简便的工艺制备模板粒子以及空心粒子，以期附载、包裹特定的活性物质、药物、生物分子等。模板粒子的制备：依据作者在专利ZL 200310115329.4中报道的技术工艺制备模板粒子[29]，将马来酸酐与醋酸乙烯酯两种单体按一定浓度和配比溶解在酯类介质(如乙酸丁酯)中，使用常规的过氧化物或偶氮类引发剂，聚合得到稳定的乳胶粒子分散体系。该体系是一个不需任何稳定剂的分散聚合(“自分散”聚合)体系，不仅可以简化工艺操作，而且得到的高分子粒子表面洁净，表面性能优异[30-33]。图1透射电子显微镜图片显示，所制备模板粒子的球形性好，而且粒度均匀，接近单分散性。进一步的研究发现，该方法制备的高分子粒子的粒径可以通过单体浓度、单体配比、溶剂性质等一系列参数在很大的尺度范围内进行调节(20 nm-5 μm)。图2的红外谱图显示，1 785 cm-1和1 859 cm-1处出现酸酐基团的两个特征吸收峰，1 744 cm-1处出现酯基的特征吸收峰，表明上述高分子粒子的化学组成是马来酸酐与醋酸乙烯酯的共聚物。该共聚物可以很容易地溶解于水、酮类以及醇类介质当中，很适合作为模板粒子使用。空心粒子的制备：在模板粒子的表面引发种子聚合，制备出核-壳结构的高分子粒子，继而用模板内核的良溶剂溶去核-壳粒子中的内核，可以制备出粒度均匀、壁厚均一的高分子空心结构粒子。上述方法制备的高分子纳米空心粒子的分子结构中同时包含酸酐基团和吡咯烷酮基团，是一种新型化学组成的表功能化的纳米空心粒子。粒子空腔的内外表面具有高反应活性的酸酐基团和高络合活性的吡咯烷酮基团，可以通过化学键合方式附载、包裹特定的活性物质、药物、生物分子、肿瘤靶向剂、抗体等，从而有利于高分子纳米空心粒子在生物医药领域的应用。用HITACHI H-800透射电子显微镜观察高分子纳米空心粒子的形貌，用Malvern Mastersize 2000激光粒度分析仪测定空心粒子的粒径和粒径分布，数据统计分析方法如下：式中di为单个微球粒径；dn为微球数均粒径；dw为微球重均粒径；n为样本容量；PDI为粒径分布指数。由透射电镜图可以看出，高分子空心粒子的粒径比较均匀(图3)，而且空心粒子的壁厚可以进行调控，具体数据见表1所示。由于空心粒子的外壳由交联的片状结构相互叠加而成，所以片层之间有丰富的孔隙，这种微观的片层间隙为模板粒子的分子链被溶剂溶出提供了通道，而且为药物分子、生物分子的吸附、释放提供了通道，有利于空心粒子在生物医药领域的应用。 2.2 空心粒子附载血竭的工艺探讨及应用展望利用高分子纳米空心粒子比表面积大、吸附性强，而且其空心部分可容纳大量的客体分子的特性，可将其用于药物载体材料，从而产生一些奇特的基于微观包裹效应的性质。将中药血竭溶解于其良溶剂乙醇、异丙醇或者酯类溶剂中，配成接近饱和的溶液，然后将上述制备的高分子空速离心机分离，用溶剂对离心产物进行洗涤，再次离心分离、洗涤，重复3次，以洗尽游离血竭成分；将最终的离心产物放入真空烘箱，于室温下干燥至恒重，得到附载血竭成分的纳米粒子。将血竭制成纳米级的微乳颗粒，可以形成以水为介质的“溶液”，提高血竭的可吸收性和生物利用度。血竭纳米粒子在肠道内通过粘膜由小肠绒毛的尖部直接吸收进入血液循环，生物利用度可达90%以上。而且其微乳化缓释作用使血竭不良反应小、用药量低、作用时间长，有望制成粉剂、片剂、膏剂、胶囊剂甚至针剂等剂型。纳米级微乳化血竭针剂有望可进行静脉注射，随着血液有效到达病灶，治疗血瘀、心脑血管等多种疾病。通过调控纳米空心粒子壳的厚度和孔隙率，可以控制药物的释放速率；通过粒子表面的生物化学修饰，可以使载药粒子具有靶向特性。本部分的工作将在后续系列文章中进行报道。"

References

[1] 朱卫东,孙志琴.龙血竭的药理作用研究[J].黑龙江医药, 2006, 19(5):403-404.
[2] 林芳,任杰红.血竭的药效学研究[J].云南中医中药杂志, 1999, 20(1):31-33.
[3] 锦亮,江东福.云南血竭的化学成分及抗真菌活性[J].云南植物研究,1995,17(3):336-340.
[4] 屠鹏飞,陶晶,胡迎庆.龙血竭黄酮类成分研究[J].中国中药杂志, 2003,1(1):27-29.
[5] 申秀民.广西血竭化学成分的研究[J].中草药,2004,35(7):728.
[6] 陈定芳,宋启示.血竭资源开发的研究进展[J].广州中医药大学学报,2004,21(6):489-492.
[7] 蓝鸣生.龙血竭研究进展[J].医学文选,2005,24(6):1053-1055.
[8] 徐淑卿,沙明,孟宪生.血竭的稳定性研究[J].中成药,2005,27(5): 598-601.
[9] 南莉莉,张超,杜娟,等.现代口服药物的吸收问题及促吸收方法的概述[J].上海医药,2008,29(8):355-358.
[10] Kawaguchi H.Functional polymer microspheres. Prog Polym Sci.2000;25:1171-1210.
[11] Ugelstad J,Berge A,Ellingsen T,et al.Preparation and application of new monosized polymer particles. Prog Polym Sci.1992;17:87-161.
[12] Uhlen M.Magnetic separation of DNA. Nature. 1989;340: 733-734.
[13] Rembaum A,Yen RGK,Kempner DH,et al.Cell labelling and magnetic separation by means of immunoreagents based on polyacrolein microspheres. J Immunol Methods.1982; 52: 341-351.
[14] Li X,Sun Z.Synthesis of magnetic polymer microspheres and application for immobilization of proteinase of balillus sublitis. J Appl Polym Sci.1995;58: 1991-1997.
[15] Ugelstad J,Søderberg L,Berge A,et al.Monodisperse polymer particles: a step forward for chromatography. Nature. 1983; 303:95-96.
[16] Xia Y,Gates B,Yin Y,et al.Monodispersed colloidal spheres: Old materials with new applications. Adv Mater. 2000;12: 693-713.
[17] Schärtl W.Crosslinked spherical nanoparticles with core-shell topology. Adv Mater. 2000;12:1899-1908.
[18] Caruso F. Nanoengineering of particle surfaces. Adv Mater. 2001; 13:11-22.
[19] 何卫东,潘才元.核壳聚合物粒子[J].功能高分子学报, 1997, 10(1): 110-117.
[20] 官建国,邓惠勇,王维,等.以胶体粒子为模板制备核壳纳米复合粒子[J].化学进展,2004,16(3):327-334.
[21] 乐园,陈建峰,汪文川.空心微球型纳米结构材料的制备及应用进展[J].化工进展,2004,23(6):595-599.
[22] Kumar V,Banker GS.Target-oriented Drug Delivery Systems[A].In: Banker GS. Rbodes CT eds. Modern Pharmaceutics. 3ed. NewYork: Mareel Dekker,1996:611-680.
[23] 陆彬.药剂学[M].北京:中国医药科技出版社,2003:437.
[24] 廖工铁.靶向给药制剂[M].成都:四川科学技术出版社,1997.
[25] 李凤前,胡晋红.肝靶向给药系统研究的新进展[J].中国药学杂志, 2002,37(5):321-325.
[26] 曹同玉,刘庆普,胡金生.聚合物乳液合成原理、性能及应用[M].北京:化学工业出版社,1997.
[27] Kamiyama M,Koyama K,Matsuda H,et al.Micron-sized polymeric microsphere by suspension polymerization.J Appl Polym Sci.1993;50:107-113.
[28] 于涌,杨万泰.高交联反应性空心聚合物微球的制备及其表面吸附纳米银粒子的应用[D]. 北京化工大学博士学位论文,2007.
[29] 杨万泰,邢长民.一种马来酸酐与醋酸乙烯酯共聚反应的方法,专利号：ZL 200310115329.4.
[30] Xing CM,Yang WT.A Novel Facile Method for the Preparation of Uniform Reactive Maleic Anhydride/Vinyl Acetate Copolymer Micro- and Nanospheres. Macromol Rap Commun. 2004;25:1568-1574.
[31] Xing CM,Hong Y,Dong Y,et al.Novel Fluorescent Polymer Nanoparticles with Chemically Bonded Tetraphenylethylene Derivatives. 233rd ACS National Meeting, Division of Polymer Chemistry, USA,2007;48:466-467. 　　　
[32] Xing CM,Yu Y,Yang WT.Stabilizer-Free Dispersion Copolymerization of Maleic Anhydride and Vinyl Acetate. I. Effects of Principal Factors on Microspheres. J Polym Sci A. 2005;43:3760-3770. 　　
[33] Xing CM,Yu Y,Yang WT.Stabilizer-Free Dispersion Copolymerization of Maleic Anhydride and Vinyl Acetate. II. Polymerization Features.Macromol Chem Phys. 2006;207(6): 621-626.