【作者】 谢皓东；

【导师】 屈树新；

【作者基本信息】 西南交通大学 ， 生物医学工程， 2008， 硕士

【摘要】 由于磷酸钙骨水泥具有优良的生物学性能、可在室温下塑形、自固化、固化时基本不放热等优点,已作为骨修复材料被成功地应用于临床。尤其是磷酸钙骨水泥的制备不需要经过高温过程,不会影响药物的药性,因此磷酸钙骨水泥适合作为药物载体材料。目前已有大量关于磷酸钙骨水泥作为整体来研究其载药和释放情况,包括磷酸钙骨水泥的粉液比,凝固时间,载药量,力学强度和晶体颗粒大小等因素的影响研究。磷酸钙骨水泥一般由一种或一种以上磷酸钙盐混合成粉相,与磷酸缓冲液、血清等液相混合而成,迄今已报道的磷酸钙骨水泥的配方多达200多种,而对于每种单个磷酸钙盐的载药和释放药物研究尚未见报道。本课题组前期已开展了载中药磷酸钙粉末和磷酸钙骨水泥的制备和表征,比较不同载药方式对磷酸钙载中药的影响,体外细胞培养评价载中药的磷酸钙的生物活性等。但是,关于每种磷酸钙盐的药物释放规律,药物剂量对每种磷酸钙盐载药的影响以及不同的材料学性能对各种磷酸钙盐的载药影响尚未进行。因此本实验的主要目的是研究磷酸钙载药系统影响药物释放的因素,主要内容包括:研究不同钙/磷比的磷酸钙钙盐载药和对药物控释的影响:不同的药物剂量对不同钙/磷比的磷酸钙钙盐药物控释的影响;研究磷酸钙的不同材料学特征如:比表面积和粒度等对药物控释的影响。本实验选用中药丹参注射液,通过湿法共沉淀反应合成含丹参(SMB)的羟基磷酸钙(HA/SMB)、缺钙的羟基磷灰石(CDHA/SMB)和磷酸氢钙(DCP/SMB),通过控制加入的丹参药量,制备含不同剂量的载中药(丹参)磷酸钙。实验中未载中药的各种磷酸钙盐作为空白组,分别采用X射线衍射(XRD)和红外吸收光谱(FT-IR),激光粒度仪和比表面积仪等分析各种载药或未载药磷酸钙。体外释放实验在37℃的模拟体液(SBF)中进行,各组磷酸钙浸泡在SBF中,在选定的时间点测量SBF中的pH值、SMB的紫外吸光度值、以及钙离子浓度的变化情况,浸泡前后的磷酸钙进行热分析。实验结果表明:1、通过在湿法合成磷酸钙的过程中加入中药丹参,可制各各种载中药丹参的磷酸钙,丹参的加入对HA和CDHA的晶相无影响,但导致其某些晶面的取向生长,而对DCP基本无影响。这主要是由于DCP成核和生长速率较快,易形成较大尺寸的颗粒。三种磷酸钙盐的比表面积随着钙磷比的增加而增加,粒度随着钙磷比的增加而减小。比表面积和粒度对丹参的载药-体外释放有着很大影响,比表面积的增加提高了磷酸钙材料的吸附能力。因此,三种磷酸钙盐的载药量:HA＞CDHA＞DCP。2、不同剂量的丹参对三种磷酸钙盐的载药-体外释放研究表明,随着丹参剂量的增加,磷酸钙/丹参中丹参的含量随之增加。每种磷酸钙盐的丹参释放量也随之增加,药物释放规律为释放初期(12小时内),药物浓度变化紊乱,随时间的增加,药物释放量增加并逐渐趋于稳定,药物释放量的大小:CaP/50＞CaP/40＞CaP/30。钙离子的浓度也随着丹参的释放而增加,CaP/50＞CaP/40＞CaP/30,pH值的变化主要受释放的丹参影响,随着丹参的释放量增加pH值降低的越多,浸泡不同剂量的磷酸钙/丹参的SBF的pH值大小为CaP/50＜CaP/40＜CaP/30,均在7.2～7.4范围内变化,符合人体生理条件。丹参剂量的变化对HA的载药量和释放影响最大,对CDHA的影响次之,对DCP的影响最小。3、不同钙磷比磷酸钙盐的载药-体外释放研究表明,随着钙磷比的增加,磷酸钙/丹参中丹参的含量随之增加,体外释放的丹参药量也随着钙磷比的增加而增加,即HA/SMB＞CDHA/SMB＞DCP/SMB;药物释放规律为释放初期(12小时内),药物浓度变化紊乱,随时间的增加,药物释放量增加并逐渐趋于稳定。pH值的变化主要受释放的丹参影响,浸泡磷酸钙盐的SBF的pH值大小为CDHA/SMB＜HA/SMB＜DCP/SMB,均在7.2～7.4范围内变化,符合人体生理条件,钙离子浓度主要受磷酸钙的溶解度和丹参扩散影响,在此pH值范围三种磷酸钙盐的溶解度大小DCP＞HA＞CDHA,但是丹参的扩散促进了磷酸钙盐的溶解。所以测得的钙离子浓度CDHA/SMB＜HA/SMB＜DCP/SMB。4、通过对比加载对乙酰氨基酚(PC)和丹参两种不同剂型的药物到CDHA和DCP中,PC和丹参的加入对CDHA的晶相无影响,但导致其某些晶面的取向生长,PC较丹参的影响更大,两种药物对DCP都基本无影响。随着PC剂量的增加,磷酸钙/PC中PC的含量随之增加。综上所述,药物的载入对磷酸钙的晶相无影响;随着药物剂量的增加,磷酸钙的载药量和释放量随之增加;随着钙磷比的增加,磷酸钙的载药量和释放量随之增加;不同药物的加入对磷酸钙的晶相影响不同,PC较丹参影响更大。三种磷酸钙中,HA为最好的药物载体,DCP的吸附性能最低。更多还原

【Abstract】 It has been wildy investigated using Calcium Phosphate Cements（CPCs） as Drug Delivery System. In particular, CPCs can be prepared without the high temperature process, which provide the possibility to use CPCs as delivery systems for some growth factors or some drugs in orthopaedic to improve the concrescence of bone fraction. It is well known that all CPCs are formed by a combination of one or more calcium phosphates, upon mixing with the liquid phase, usually water or an aqueous solution, then becomes the paste to set and harden in ambient or after being implanted. Up to date, there are more than 200 kinds of CPCs. Amounts studies demonstrated that the release of drugs from CPCs depended on different factors such as the microstructure, the drug solubility, the type of bond between the drug and the matrix which holds it, and the mechanism of degradation of the matrix. However, it is unclear that the mechanism of the drug load and release from various typies of calcium phosphate. In our group, CaP biomaterials, including in CaP powders and CPCs loading Chinese medicne, Salvia Miltiorrhiza Bunge （SMB）, which is a well-known and inexpensive Chinese medicine herb under the traditional Chinese name Dan-shen, have been prepared and characterized recently. However, the release of SMB from various types of calcium phosphate is also unclear.In this study, three kinds of Ca/P powders, Hydroxyapatite（HA）, Calcium Deficient Hydroxyapatite（CDHA） and Dicalcium phosphate （DCP） with Ca/P molar ratios 1.67, 1.50 and 1.00, were synthesized through the wet chemical method accompanying with SMB injection, respectively. All filtration cakes were dried at 65℃until their weights without change and milled to powders. As-received CaP powders with and without SMB were soaked in simulated body fluid （ SBF ） up to 360 h at 37℃with the solid to liquid ratio of 1 : 10. Meanwhile, the reaction products were characterized by X-ray diffraction analysis （XRD）, Ultraviolet-Visible Spectrometry （UV-VIS）, Thermal Analysis （TA）, pH meter and Atomic Absorption Spectrum （AAS） to investigate the influence of factors on drug delivery.Based on the present results, it was concluded:1. The SMB could be added on the calcium phosphate through the wet chemical method accompanying with the SMB injection. The addition of the SMB to the calcium phosphate had no effect on their phase, especially the DCP. This was mainly due to the fast nucleation and growth rate of DCP resulting in larger size particles formed with the smaller specific surface area. The absorbability increased with the calcium phosphate molar rate increasing which led to the increasing content of the SMB contained in various CaP.2. The content of SMB in calcium phosphate drug delivery system would increase with the increase of the SMB injection dosage. The more content of SMB would promote the SMB releasing. In the initial 12 hours of the releasing, drug concentration was in disorder. Then it increased gradually and became stable. The releasing quantity of the SMB and the Ca²⁺ concentration increased with the SMB dosage increasing. The order was CaP/50>CaP/40>CaP/30. But the change of the pH value was contrasted with the Ca²⁺ result. This was mainly due to the pH value decreased with the quantity of the SMB increasing. The dosage of the SMB had more influence in the releasing of the HA than the DCP.3. The result of the releasing of the SMB showed that the releasing quantity of the SMB was increased with the calcium phosphate molar rate increasing. The SMB released from the CaP powders accompanying with the degradation of CaP. The order of the three calcium phosphates solution was DCP>CDHA>HA at the scope of pH value from 7.2 to 7.4. But the release of the SMB stimulated the dissolution of the CaP. So the Ca²⁺ concentration and the pH value had been affected by the release of the SMB. And the order of the Ca²⁺ concentration and the pH value of the three CaP/SMB was CDHA/SMB < HA/SMB <DCP/SMB.4. By comparing the paracetamol（PC） and the SMB loaded on the calcium phosphate, it indicated that the two kinds of drugs had different effect on the crystallinity of the CaP. The effect of the paracetamol（PC） on the crystallinity was more significant than the SMB.In conclusion, the HA have been indicated as the best SMB carrier, the DCP was the worst in the present study. This study would be benefit for us to prepare CPCs loading with drug through various types of calcium phosphate to carry out the drug control release.更多还原