乳化交联法制备壳聚糖微球粘连原因分析

乳化交联法是制备壳聚糖微球常用的工艺，但在制备过程中，常出现微球产物粘连的现象。分析了搅拌速度、油水体积比、表面活性剂添加量和交联剂用量等影响微球粘连的因素，优化出了分散性好，粒度均匀的壳聚糖微球制备工艺参数。结果表明，搅拌速度〉350r／min，油水体积比〉2．5，表面活性剂span80用量为水相的20％时，可获得分散性好的壳聚糖微球，微球的粒径可以控制在1～5μm之间。     

膜乳化法制备单分散高分子微球和微囊的研究进展

膜乳化法不仅是获得高质量单分散稳定乳液的一种简单有效方法，也是制备单分散功能性微球和微囊的有效手段．着重介绍了用膜乳化法制备单分散药物载体微球和微囊、色谱柱填料微球和电子摄影调色剂微球，以及其它单分散高分子微球和微囊方面的研究成果．     

单分散中空聚苯乙烯微球制备

采用搅拌乳化方法制备水包油(W1/O)型乳状液,经膜乳化法制得单分散的复乳(W1/O/W2)型乳状液,再通过液中干燥法制得单分散中空聚苯乙烯(PS)微球.考察了shirasu porous glass(SPG)膜孔径对乳状液液滴粒径及粒径分布、表面活性剂浓度对PS微球中空率和单分散性的影响.由激光粒度分析仪结果及PS微球的SEM照片证实,制得的PS微球,粒径呈单分散,是SPG膜孔径的2.0～2.4倍且具有中空结构.     

壳聚糖微球的制备与应用

壳聚糖微球是一种典型的生物医用材料,主要应用于药物、杀菌、基因治疗等领域.目前,壳聚糖微球的常用制备方法有化学交联法、离子交换法、复凝聚法、喷雾干燥法和乳化分散法等.分析了壳聚糖微球的主要制备方法,评述了其在药物负载、伤口杀菌、基因治疗等领域的应用.     

无皂乳液聚合法制备单分散聚苯乙烯微球

以苯乙烯(St)为单体,过硫酸钾(KPS)为引发剂,采用无皂乳液聚合法制备了聚苯乙烯微球。研究了单体、引发剂的浓度,引发剂加入方式,聚合温度对制备PS微球粒径的影响。运用傅立叶红外光谱(FT-IR)、透射电子显微镜(TEM)、场发射扫描电镜(FE-SEM)、电势与纳米粒径分析仪等手段,对微球的组成成分、表面形态、粒径及其分布、表面电势进行了表征。结果表明微球粒径均匀,在100～200nm范围内,球形度良好且呈单分散性。     

单分散聚苯乙烯微球的制备

用分散聚合方法制备单分散聚苯乙烯微球，用扫描电镜测定了微球粒径大小和分布，随着介质溶解度的大小，微球的粒径先增大而后减小，引发剂浓度的提高微粒径的增大和粒径分散系数的变大。     

静电喷雾法制备壳聚糖/康普瑞丁载药微球

本研究采用静电喷雾法,以壳聚糖为基质材料,康普瑞丁为模型药物制备微球。实验中采用AcOH/H2O和AcOH/H2O/EtOH两种溶剂,分析了微球形貌和粒径分布的影响因素,并且对CS-CA4微球的缓释性能进行了测定。结果表明,壳聚糖浓度、溶剂配比及乙醇和康普瑞丁的加入会使壳聚糖微球呈球状、中间塌陷的类球状、棒状等不同形貌,微球粒径存在较大差异;通过AcOH/H2O/EtOH复合溶剂将疏水性药物康普瑞丁载入壳聚糖微球,制备出的壳聚糖/康普瑞丁载药微球分散性好,粒径分布均匀,平均粒径仅为0.27μm;使用戊二醛蒸汽交联48h的微球缓释效果明显。     

核孔膜生产线膜微孔制备工艺实验研究

本文介绍核孔膜生产线,重点描述了膜微孔制备工艺的实验研究。对于PC和PES膜,已得到32种工况下的扩孔公式,其形式为D=A+Bt,其中D——孔径,t——扩孔时间,A,B为特定工艺参数下的常数值.通过实验。得到了膜孔密度N与300~#核反应堆功率P、热柱辐照位置L的经验公式,即N=6.97×10~5×10~3×101~(1.18L).在本生产线上可生产最大幅面为3 140mm×240mm,孔径为0.04～10 μm的多系列多规格的核孔膜产品。     

乳化交联法制备聚乙烯醇微球的工艺研究

采用乳化交联法,以含有表面活性剂的植物油为连续相(油相),聚乙烯醇(PVA)水溶液为分散相(水相),戊二醛为交联剂,盐酸为催化剂,制备了PVA微球.利用FT-IR、SEM及粒度分析仪等设备对微球的组成、形貌及粒径分布进行了测试,并考察了几种关键工艺参数对微球制备的影响.结果表明,在PVA溶液浓度为5％,表面活性剂采用2 g脱水山梨醇单油酸酯(Span 80),乳化温度为50℃,1mol/L稀盐酸催化戊二醛交联的条件下,可以获得球形规整、表面光滑且分散性好的PVA微球.粒径分析结果显示,所得PVA微球的平均粒径约为25 μm,且分布在15～45 μm范围内的微球约占其总量的80％.     

新型水溶性壳聚糖盐酸盐微球的制备与表征

以水溶性壳聚糖盐酸盐为原料,戊二醛为交联剂,采用乳化交联法制备了壳聚糖盐酸盐微球。通过多种理化手段检测及体外MG63细胞共培养对壳聚糖盐酸盐微球的形貌结构、尺寸大小、粒径分布、成球机理、结晶度、热稳定性及细胞相容性进行了测试及表征,并与普通酸溶性壳聚糖制备的微球进行比较。结果表明水溶性壳聚糖盐酸盐与戊二醛通过Schiff碱反应产生交联,易成球,球形圆整光滑;粒径分布较窄,粒径约为5～10μm;微球结晶度较低,其热稳定性较壳聚糖盐酸盐原料和酸溶性壳聚糖微球均有提高;细胞相容性良好。该微球表现出与酸溶性壳聚糖微球相似的理化性质,但因其原料为水溶性,微球制备条件更为温和,在药物载体研究领域有望得到更广泛的应用。     

Preparation of carbon aerogel microspheres by a simple-injection emulsification method

Carbon aerogel microspheres were successfully prepared using a simple-injection emulsification method, employing sol–gel polycondensation of a resorcinol–formaldehyde solution containing sodium carbonate as a catalyst. This process was followed by solvent exchange using acetone, supercritical drying with carbon dioxide and carbonization in a nitrogen atmosphere. The effect of curing time before starting injection, injection rate and agitation rate of continuous phase on the particle size and the porous properties of the carbon aerogel microspheres was investigated. Adsorption of phenol by using the prepared carbon aerogel microspheres was also examined. The diameter of carbon aerogel microspheres was controlled in the range of 20–55 μm by varying injection rate and agitation rate. The mean diameter of carbon aerogel microspheres decreased with increasing the injection rate and the agitation rate, whereas their mean diameter was independent of the curing time. The BET surface area and total pore volume of carbon aerogel microspheres increased with increasing the curing time. In contrast, their BET surface area and total pore volume decreased with increasing the injection rate and the agitation rate. The BET surface area, total pore volume, mesopore volume and micropore volume of the carbon aerogel microspheres with a mean diameter of 45 μm were 903 m²/g, 0.60 cm³/g, 0.31 cm³/g and 0.27 cm³/g, respectively. The phenol-adsorption capacity of these carbon aerogel microspheres was 29.3 mg phenol/g adsorbent.     

Preparation of the novel alkylated chitosan microspheres

制备N--烷基化改性壳聚糖微球, 研究了溶液pH值、2,4-二硝基酚浓度、温度和氯化钠含量等因素对其吸附性能的影响. 结果表明,庚醛改性壳聚糖微球具有较好的抗酸碱性能;溶液的pH值对庚醛改性壳聚糖微球吸附性能的影响较大, pH值为3.6、吸附时间为1 h时,对2, 4--二硝基酚的吸附量最大(达到400 mg×g-1);2, 4--二硝基酚浓度对吸附的影响符合Freundlich等温方程;改性壳聚糖微球对2, 4-二硝基酚的吸附性能明显优于未改性的壳聚糖,对浓度为15 mg×L-1的2, 4--二硝基酚溶液的吸附量分别为3.0 mg×g-1和1.45 mg×g-1.     

双氯灭痛壳聚糖水凝胶微球的制备及其性能研究

在Span80与植物油形成的反相胶束体系中,通过戊二醛交联制备出壳聚糖水凝胶微球(CHM)。采用红外光谱和透射电镜等方法对CHM结构及粒子形态进行了研究。同时对CHM的溶胀度及其对模型药物双氯灭痛的体外释放行为进行了考察。结果表明,CHM具有较好的控制药物释放的作用。交联程度对微球粒径、溶胀度及药物释放性能影响较大。     

Preparation and characterization of chitosan microspheres containing doxifluridine

Chitosan microspheres containing 5-fluorouracil (5-FU), tegafur (FT), and doxifluridine (DFUR) were prepared by the dry-in-oil method using silicone oil with no surfactant as a dispersion medium. For DFUR-containing chitosan microspheres (DFUR-M), reacetylation with acetic anhydride or coating using chitosan and glutaraldehyde was performed. DFUR-M, reacetylated DFUR-M, and chitosan-coated DFUR-M were investigated on in vitro drug release, and the former two microspheres were examined for in vivo degradation after subcutaneous (s.c.) implantation in mice, and in vivo plasma concentration-time profiles after s.c. implantation in rats. The present method gave fairly large microspheres purely composed of chitosan and drug because of no use of surfactant, which showed the mean particle diameters of 300-900 µm and the drug contents of 4-22% (w/w). Encapsulation efficiency of DFUR was higher than that of 5-FU and FT. DFUR-M and reacetylated DFUR-M exhibited spherical shape except chitosan-coated DFUR-M. DFUR-M showed high initial rapid release, which was suppressed to some extent by reacetylation or chitosan coating. DFUR-M and reacetylated DFUR-M subcutaneously implanted were gradually degraded, and approximately half or a little more of the microspheres disappeared from the implanted site at 3 weeks postimplantation. DFUR-M and reacetylated DFUR-M implanted subcutaneously gave similar plasma concentration-time profiles of DFUR, which did not indicate prolonged release in vivo. DFUR-containing chitosan microspheres with fairly large size and good drug content could be obtained by the present preparation but remained to be improved for drug release properties.     

Preparation and blood coagulation evaluation of chitosan microspheres

Cross-linked chitosan microspheres (40–100 μm) with smooth surface were prepared by the methods of emulsification and ethanol coagulant. FTIR results showed that the cross-linking reaction occurred on the amino groups of chitosan molecules. The swelling characteristic of chitosan microspheres was influenced by the environment pH, being generally greater at low rather than higher pH values. The coagulation properties of chitosan microspheres were evaluated by dynamic blood clotting, platelet adhesion and activation, erythrocyte adhesion, hemolysis, and protein absorption assays. Chitosan microspheres can shorten the clotting time and induce the adhesion and activation of platelets. But the shortening of clotting time by chitosan microspheres may be related to not only platelet aggregation, but also erythrocyte aggregation. Take together, chitosan microspheres may be potential use as thrombospheres.