节点文献
葛根素磷脂固体分散物的研究
【作者】 翟光喜；
【作者基本信息】 沈阳药科大学 ， 药剂学， 2003， 博士
【摘要】 葛根素是中药葛根的主要有效成分，临床上广泛用于治疗心脑血管疾病；由于其口服难吸收、生物利用度低的原因，临床只用于静脉给药。这不仅给患者带来用药的不便，而且也限制了葛根素的临床应用。本课题根据国外文献将葛根素与磷脂制成固体分散物，以期通过这一技术改善葛根素非静脉给药的生物利用度，探索一条促进中药活性成分体内吸收的途径，并研究磷脂作为载体形成固体分散物的特点。 研究制备了葛根素磷脂固体分散物，对其物理化学性质进行了较为系统和深入的研究，在此基础上对其形成机理进行了分析和探讨，并进行了初步稳定性与生物学特性的研究。主要包括葛根素磷脂固体分散物制备的影响因素考察、存在物态、溶解性能、热力学性质、形成机理、动物体内的吸收与分布及药效学等方面的实验研究。至今为止，尚未在国内外的文献中见到有关葛根素磷脂固体分散物的研究与应用的报道。 以共沉淀的方法制备了葛根素磷脂固体分散物，并对可能影响工艺的因素如溶剂、药物浓度、温度、反应时间等进行了考察，确定了以乙醇为溶剂，反应条件简单易行的制备工艺。 用光学显微镜观察了葛根素磷脂固体分散物的微观形态，结果表明：与物理混合物相比，固体分散物粒子分散更为均匀。以X-射线衍射法对其物态研究的结果显示，葛根素磷脂固体分散物在一定的比例范围内表现为无定形特征，葛根素自身的晶体衍射峰几乎完全消失；差热扫描分析(DSC)图谱显示葛根素与磷脂形成固体分散物后，葛根素的特征吸热峰几乎完全消失，磷脂的相变温度明显变化。在透射电镜下，可以清楚地观察到葛根素磷脂固体分散物在水中呈现脂质体的结构。对其在水和氯仿等溶剂中溶解性能的测定结果表明：固体分散物中葛根素在水和氯仿中的溶解量随磷脂比例的增大而增大，在氯仿中其增大非常显著；在正己烷、乙醚、乙酸乙酯、二氯甲烷及丙酮中溶解性能的考察结果显示随磷脂比例的增大，葛根素磷脂固体分散物在极性较小的溶剂中溶解度逐渐增大。葛根素磷脂固体分散物在pH为1.0、7.0、9.0的水溶液-正辛醇中的表观油／水分配系数均随磷脂比例的增大而增大。葛根素、槲皮素、芦丁磷脂固体分散物溶出实验表明由于磷脂固体分散物处于无定形态以及在水中可自发形成脂质体结构对难溶性药物槲皮素和芦丁有明显的溶出促进作用，而对于微溶性的葛根素溶出促进作用不明显；与同比例的聚乙二醇-槲皮素固体分散物或聚维酮-槲皮素固体分散物相比，质量沈阳药科大学博士学位论文比为1:l的棚皮素磷脂固体分散物对难溶解性棚皮素的促进作用更为显著，提示:相比于聚乙二醇或聚维酮，磷脂能以相对较小的量即可达到明显的促进药物溶出的作用。初步稳定性考察结果表明，葛根素磷脂固体分散物应在低温、干燥处存放。 采用紫外光谱(uV)、红外光谱(IR)、核磁共振光谱(NMR)以及薄层色谱(TLC)首次对葛根素磷脂固体分散物的形成机理进行了研究和推测并提出了自己的见解。与其物理混合物相比，不同比例葛根素磷脂固体分散物在氯仿中的UV吸收光谱产生了明显的变化，说明葛根素产生紫外吸收的苯环骨架结构的电子跃迁受到了磷脂的影响;而在甲醇中物理混合物与相应比例的葛根素磷脂固体分散物的UV吸收光谱完全相同。从KBr压片法测得的IR光谱可看到固体分散物中属于葛根素部分的苯环骨架共扼结构的相应峰位发生了较大变化，磷脂极性端的部分峰位也发生了较大变化。以氖代甲醇或氖代二甲基亚矾为溶媒的葛根素磷脂(质量比为1:2)固体分散物NMR光谱与其相应物理混合物NMR光谱无明显差别，说明在甲醇或二甲基亚矾中形成固体分散物的葛根素与磷脂之间的作用力被破坏;但在以氖代氯仿为溶媒的固体分散物(质量比为1:2) NMR光谱的信号几乎全部归属于磷脂，而葛根素的NMR信号消失。葛根素磷脂固体分散物的TLc图谱表明葛根素与磷脂在以甲醇氯仿水(25:65:4)为展开剂、以硅胶为固定相的薄层板上可完全分离。由以上实验结果并结合葛根素与磷脂的分子结构及理化性质分析认为:葛根素磷脂固体分散物可能是通过葛根素分子的苯环共扼骨架结构(可作为电荷供体)与磷脂分子的碱基部分(可作为电荷受体)形成电荷迁移力、葛根素葡萄糖环上的轻基基团与磷脂分子的磷酸基团形成氢键以及范德华作用力等形成的。 采用葛根素为对照的交叉实验设计，进行了葛根素磷脂固体分散物大鼠口服吸收的研究，结果表明葛根素磷脂固体分散物可改善葛根素的口服吸收，提高生物利用度。首次将磷脂固体分散物用于透皮吸收，将几种比例的葛根素磷脂固体分散物与相应量的水混合形成具有触变性质的半固体混合物，其对葛根素经离体小鼠皮肤渗透的影响试验表明葛根素与磷脂形成固体分散物可明显促进葛根素对离体小鼠皮肤的渗透，在研究范围内(葛根素一磷脂6:1、4:1、3:1，w/们随磷脂比例的增大，对葛根素经皮渗透的促进作用也逐渐增大。以葛根素为对照，首次研究了质量比为1:l的葛根素磷脂固体分散物经家兔鼻腔喷雾给药葛根素经鼻戮膜的吸收及体内分布，并建立了新的灵敏的测定血浆和组织浆液中葛根素的HPLC方法，结果?
【Abstract】 As the main active constituent of Pueraria Lobata Ohwi, Puerarin can widely be used for treatment of cerebro-cardiac vascular diseases. However, for the sake of its low oral absorption and bioavailability, now in clinic Puerarin is administrated only by vein injection, which is inconvenient for patients and limits its clinical use. By the technology of forming phospholipid solid dispersion, the aim of present research is to enhance the bioavailability and to explore a way that can help enlarge the absorption of the active constituents of Chinese Traditional Drugs.The present research focuses on the reaction mechanism of Puerarin-phospholipid solid dispersion and its physicochemical and biological characteristics. In order to provide a scientific basis for the development and application of the study, a series of experiments have been performed in the preparation, the reaction mechanism, the physicochemical properties, the stability, the absorption and tissue distribution characteristics in animals through nasal administration and the biological activity. Up to now, no report about the study of Puerarin-phospholipid solid dispersion at home and abroad is found.Solid dispersions of Puerarin-phospholipid are prepared through co-precipitation, and the effecting factors such as solvent, drug concentration, temperature, reaction time are examined. The technological using alcohol as solvent with a simple reaction condition is determined.The microcosmic form of the solid dispersion of Puerarin-phospholipid is observed under microscope, the results show that compared with the physical mixture, the size of particles of solid dispersion of Puerarin-phospholipid is more even. X-Ray powder diffraction analysis exhibits that the solid dispersion of Puerarin-phospholipid was in an amorphous form in a specific proportion range of the two components, and the crystal diffraction peaks of Puerarin almost completely disappear. The DSC curves prove that after forming the solid dispersion with phospholipid, the thermal characteristic of Puerarin is increasingly sheltered by phospholipid with the increasing proportion of phospholipid. It can be observed with transmission electron microscope that when treated with water the solid dispersion of Puerarin-phospholipid formed into the liposome structure. It is shown that a great improvement of apparent solubility of Puerarin in solid dispersion in water and in chloroformwith the increasing of the proportion of phospholipid, especially significant in chloroform. Study on the solubility in hexane, ether, ethyl acetate, dichloroethane and acetone indicates that with the increasing proportion of phospholipid, solubility of Puerarin in solid dispersion in the low polar solvent raises. The enhancement of apparent oil/water partition coefficient of solid diserison in n-octyl alcohol-water (pH 1.0, 7.0, 9.0) system is found. The experiment results of the dissolution of solid dispersion of Puerarin-phospholipid, Quercetin-phospholipid, Ruting-phospholipid show that phospholipid solid dispersion has an obvious dissolution enhancing effect on the insoluble Quercetin and Rutin, but not obviously for slight soluble Puerarin. Compared with the solid dispersion of polyethylene glycol-Quercetin and polyvinglyrrolidone-Quercetin (l:l,w/w), the solid dispersion of Quercetin-phospholipid in the same proportion has more obvious effect on the dissolution of Quercetin. It shows that compared with polyethylene glycol or polyvinglyrrolidone, phospholipid as a carrier in a small amount could have an obvious dissolution enchancing effect. The research on stability of solid dispersions of Puerarin-phospholipid shows that they should be kept in a low temperature and dry condition.It is the first time to study and conjecture the forming mechanism with ultraviolet spectra, infrared spectra, nuclear magnetic resonance spectra and thin layer chromatogram, and a new idea is put forward. Compared with its physical mixture, the UV absorption spectra in chloroform of solid dispersion of Puerarin-phospholipid i