Characteristic and in vitro bioactivity of a microarc-oxidized TiO(2)-based coating after chemical treatment

Microarc oxidation (MAO) was used to prepare a TiO(2)-based coating containing Ca and P on titanium alloy. An alkali treatment was developed to modify the surface of the MAO coating to improve the apatite-forming ability of the coating. The chemically treated MAO coating exhibits a modified layer, with the main constituents being O, Ti, Ca and Na, showing anatase. The modified MAO coating shows a rough and porous morphology containing numerous nanoflakes of approximately 100nm thickness. During the alkali treatment process, P on the surface of the MAO coating shows a main dynamic process of dissolution; however, Ca exhibits a re-deposition process as well as dissolution. The formation of the modified layer could be explained by this mechanism: negatively charged HTiO(3)(-) ions are formed on the MAO coating due to the attack of OH(-) ions on the TiO(2) phase. The HTiO(3)(-) ions could incorporate sodium from the alkali solution and calcium from the alkali solution and MAO coating. The apatite-forming ability of the MAO coating is improved remarkably by the simple chemical treatment, since the surface of the alkali-treated MAO coating could provide abundant Ti-OH groups probably formed by ionic exchanges between (Ca2+, Na+) ions of the alkali-treated MAO coating and H3O+ ions of a simulated body fluid (SBF). Moreover, Ca released from the alkali-treated MAO coating increases the degree of supersaturation of SBF, promoting the formation of apatite. The apatite induced by the alkali-treated MAO coating possesses carbonated structure and pore networks on the nanometer scale.     

High efficiency dry coating of non-subcoated pellets for sustained drug release formulations using amino methacrylate copolymers

Abstract

Dry coating utilizing a fluidized bed was evaluated in order to produce films with sustained drug release using amino methacrylate copolymers as film former. In contrast to other dry coating procedures using amino methacrylate copolymers, the described method enables an appropriate polymer adhesion by the selection of a plasticizer additive mixture in combination with the use of a three-way nozzle for simultaneous application. Well spreading fatty acid esters were found to increase the coating efficiency from 73% to approximately 86%, when they were used in conjunction with the plasticizer. Pellets were used as drug cores without previous treatment. After a curing step at 55?°C, the pellets exhibited a prolongation of the drug release over a period of about 6?h. Mainly the three parameters, coating level, composition of the polymers in the coating mixture, and the type of plasticizer, were found to exert distinct influence on the dissolution profile. Despite the differences in the coating procedure, the dissolution profiles of the coated pellets as well as the influencing parameters were similar to those known from conventional coating techniques.     

掺杂不同离子的羟基磷灰石涂层研究现状

羟基磷灰石作为天然骨的无机组分,是良好的生物陶瓷材料,被广泛应用于惰性支架的表面改良.但在天然骨中,羟基磷灰石往往掺杂了众多离子,而这些离子对骨的新陈代谢起着一系列的作用.研究表明,离子掺杂可以有效地提高羟基磷灰石涂层的生物相容性与功能性,进而增强植入材料与骨的结合,促进周边骨组织的生长.概述了离子掺杂羟基磷灰石涂层的研究现状,并分别叙述了阳离子镁、锶、锌、锰、铜、银及阴离子硅酸根、碳酸根、氟的掺杂对于羟基磷灰石涂层的影响,对离子掺杂羟基磷灰石涂层的发展方向进行了展望.     

RGD targeting hyaluronic acid coating system for PEI-PBLG polycation gene carriers

Hyaluronic acid (HA), a natural anionic mucopolysaccharide, was used to coat polyethylenimine-poly(γ-benzyl L-glutamate)/DNA (PEI-PBLG/DNA) complexes. HA was further modified by introducing RGD peptide with grafting density of one RGD in every 1.9 HA repeating units. HA can coat the cationic surface of PEI-PBLG/DNA complexes without destroying them even at high weight ratio of HA/PEI-PBLG/DNA = 40/10/1. Coating the complexes by HA and HA-RGD caused lower surface charges and little bigger size than the naked PEI-PBLG/DNA. HA/PEI-PBLG/DNA has little lower transfection efficiency compared with naked PEI-PBLG/DNA, while the transfection efficiency of HA-RGD/PEI-PBLG/DNA is 9.7 times of HA/PEI-PBLG/DNA for the RGD target bonding affinity to the receptors on the cell surface. HA coating on PEI-PBLG/DNA reduced the electrostatic binding affinity to the cells while the RGD binding affinity for integrin on HeLa cells can not only compensate the reduced binding affinity but also enhance the affinity for HA-RGD/PEI-PBLG/DNA. RGD and RDG competition assay and lactate dehydrogenase (LDH) release studies further confirmed the specific target functions of RGD on HA. Cell viability measurements confirmed the high viability (above 70% viability) of the cells treated with HA-RGD and HA coated complex particles. These results would show that HA-RGD coated PEI-PBLG/DNA complexes have an attractive feature to a targeting in vivo non-viral gene delivery system.     

纤维桩表面经黏结剂涂层后对桩—核树脂黏结性能的影响

目的:比较桩表面2种黏结剂涂层方法对纤维桩—核树脂黏结性能的影响。方法:36根纤维桩随机分为3组,桩表面分别做3种处理。A组不处理,作为对照;B组于桩表面涂双固化黏结剂XP BondTM并光照固化;C组在桩表面涂XP BondTM,使其自固化。处理后的纤维桩与Definit Core树脂黏结制成棒状试件,分别于水存24h和1个月后进行微拉伸强度(microtensile bonding strength,μTBS)测试和扫描电镜观察。采用SPSS 13.0软件包对μTBS的测试结果进行方差分析。结果:水存24h后,C组的μTBS〔(17.03±6.01)MPa〕显著高于A组〔(9.64±4.59)MPa〕和B组〔(11.99±6.07)MPa〕,P<0.05;水存1个月后,3个实验组间的μTBS无显著差异(P>0.05)。B组和C组水存1个月后的μTBS分别为(8.17±4.25)MPa和(9.85±4.11)MPa,均比水存24h后的值显著降低(P<0.05),且在扫描电镜下观察到明显的界面裂缝。结论:黏结剂桩表面涂层对纤维桩—核树脂的即时黏结强度的作用因黏结剂的固化方式而异,2种桩表面涂层方法均会降低纤维桩—核树脂的黏结持久性。     

水分散体包衣技术在口服脉冲释药系统中的应用

水分散体包衣技术具有安全性好、无污染、能耗低、效率高的优点,具有传统有机溶剂包衣不可比拟的优势,显示出良好的应用前景.对近几年国内外水分散体包衣技术在口服脉冲释药系统中的应用进展进行综述.     

Effect of Curing Conditions and Plasticizer Level on the Release of Highly Lipophilic Drug from Coated Multiparticulate Drug Delivery System

The study aimed to investigate the effect of triethyl citrate (TEC) plasticizer level (10, 15, and 20%), curing temperature (40, 50, and 60°C) and time (0 to 168h) on the release of a highly lipophilic drug bumetanide from pellets coated with methacrylate ester copolymer (Eudragit RS). Bumetanide was layered onto sugar pellets followed by coating with 6% Eudragit RS with and without hydroxypropyl methyl cellulose (HPMC) seal coat using Wurster Fluid Bed equipment. Coated pellets were stored for 3 months at room temperature and the release was tested in USP purified water. At 10% TEC level, increasing curing time and temperature lead to slower drug release. At 15 and 20% TEC levels, curing initially decreased drug release followed by increase in the release at longer curing time and higher temperature. Drug release from coated pellets plasticized with 15% TEC and completely cured followed zero order kinetic models. At plasticizer level of 20%, bumetanide release from the completely cured pellets was better modeled using the Higuchi's equation reflecting possible drug migration during curing. Storage led to an increase in drug release. The use of HPMC seal coat stabilized drug release after storage. It was concluded that bumetanide migration into Eudragit RS film coat was the main cause of the accelerated release after curing and storage. The drug migration during storage at room temperature was prevented by seal coating the pellets with HPMC.     

Effect of lubricant on spreading of coating liquid on surface of tablets containing pancreatin

The objective of this study was to evaluate the spreading of the coating liquid on different tablets containing pancreatin and microcrystalline cellulose. The effects of the ratio of the components, the presence of magnesium stearate and the blending circumstances were investigated. The contact angle of the liquids on the different tablets did not change linearly. For the mixture containing 50% pancreatin, the deviation of the measured value from the predicted one was more than 25%. This deterioration was also detected for mixtures containing 1% lubricant, but the extent was lower and was not modified by change of the mixing circumstances. This phenomenon was explained by the special microstructure of the surface of the tablet. This was predicted from the spreading coefficient, calculated from the surface free energy. The enrichment of pancreatin on the surface was preferred in binary mixtures. The spreading of magnesium stearate was most preferred for the powder mixture, and thus prediction of the properties of the tablet was easier for these mixtures. The extent of the effect of this excipient on the surface properties was very wide-ranging. The change in the spreading of the coating liquid was significant; however, the change in the work of friction was negligible.     

pBMP/Ce-TZP陶瓷复合人工骨材料修复桡骨大段缺损的实验研究

目的：研究具有H—Z涂层的以氧化铈（CeO2）稳定的四方相氧化锆多孔陶瓷（Ce-TZP）,与猪骨形态发生蛋白（pBMP）复合成的人工骨,用于骨缺损的修复。方法：将其pBMP／Ce-TZP复合人工骨和HA复合人工骨分别植入30只家兔桡骨大段缺损处,并植入后进行X线摄片和组织学检查。结果：pBMP／Ce-TZP复合人工骨与HA复合人工骨比较,pBMP／Ce-TZP复合人工骨在结构、理化性能和生物力学强度均占有明显优势,有利于诱导成骨能力和加速新骨形成,促进骨缺损的修复。结论：pBMP／Ce-TZP复合人工骨是目前较理想的骨移植材料。     

黄腻苔病因病机及诊治应用

为探讨黄腻苔的成因及诊治经验,笔者通过查阅古籍和对CNKI、万方、维普等数据库的检索,找到合适的古文并选取相关论文进行研究,发现黄腻苔除可由湿热引起外,还可由痰热、食滞、阳虚、表邪入里、伤暑和湿温等导致;黄腻苔可出现于干咳、中风病急性期、脾胃病、肝病和肾病等疾病过程中,治法涉及清热、温补、通腑、表里双解、消食导滞、健脾祛湿和分清泌浊等,说明黄腻苔成因复杂,涉及病种繁多,治疗手段丰富多彩,临床当悉心辨析,合理施治。