丹参酮脂质体的药物渗漏和微粒聚结特性研究

考察了聚乙烯吡咯烷酮（PVP）以及冻融处理对丹参酮脂质体的药物渗漏和微粒聚结特性的影响。结果表明，丹参酮脂质体在4℃下贮存3、6．5个月后，未发现丹参酮有明显渗漏，处方中的PVP和冻融处理对丹参酮 的渗漏影响不明显；但PVP可提高丹参酮脂质体微粒的聚结活化能，并使脂质体ζ电位有所增大；脂质体混悬液在4℃下贮存3个月，不含PVP的样品粒度明显增大，并出现分层现象，而含有PVP的样品，其粒度变化甚微，混悬液均匀；而冻融处理也能使丹参酮脂质体的聚结活化能增大。     

丹参酮脂质体的制备及其稳定性

采用冻融法制备了丹参酮的脂质体,比较了冻融前后丹参酮脂质体的包封率,粒度分布,形态以及稳定性,并考察了冻融次数及冻融之后的搅拌和超声对脂质体的包封率和粒度分布的影响。结果表明,经冻融处理的丹参酮脂质体的包封率明显提高,稳定性也更好;一定范围内,脂质体的包封率和粒度随冻融次数的增加而略有增大,冻融后搅拌或超声均可使聚集的脂质体解聚,从不影响包封率的角度,搅拌比超声处理更好。     

粉尘螨脂质体的制备及稳定性考察

目的研究冻融法对粉尘螨(Dermatophagoides farinae,DF)脂质体包封率、形态及稳定性影响。方法采用逆向蒸发法制备粉尘螨脂质体悬液,冰冻高速离心法分离脂质体,透射电镜观察脂质体形态。-20℃低温冰箱冰冻,室温融化,反复5次,测定冻融前后脂质体包封率及形态变化,并用离心加速实验测定脂质体稳定性变化。结果经冻融法处理的脂质体包封率明显提高,可达(88.52±0.87)%;在一定范围内包封率随冻融次数的增加而略有增大;经离心加速实验进一步验证了冻融法可使脂质体稳定性提高。结论冻融法为一有效的脂质体制备方法。     

靶向给药系统——青蒿酯脂质体的制备研究

采用乳化法制备了多层的青蒿酯脂质体,探讨了其制备工艺、荷电性、胆固醇含量及附加剂对青蒿酯脂质体包裹率的影响。结果表明,带正电荷的脂质体其包裹率明显高于中性或带负电荷的脂质体,而类脂中胆固醇含量及附加剂对包裹率均无明显影响,最佳处方组成的包裹率为3.63±0.09％。采用冷冻干燥技术可获得稳定性较好的脂质体冻     

不同的保存条件对丹参酮脂质体粒径的影响

近来的研究表明，脂质体作为药物载体有多方面的特点，特别是在提高药物的生物利用度、降低药物的毒副作用以及提高对靶器官的选择性等方面，引起了人们的高度重视。丹参酮(tanshinone)是中药丹参中的脂溶性有效成分，不仅具有天然抗氧化性、心血管药理作用以及抗菌消炎作用，还具有明显的抗肿瘤作用。然而，丹参酮在     

脂质体不同给药系统的研究进展

脂质体是一种靶向制剂的新型药物载体材料 ,它是由磷脂和其它附加剂 (如胆固醇 )组成呈双分子层结构的微型泡囊。与其它普通制剂相比 ,脂质体能极大地提高药物的疗效、增加其稳定性及减小毒副作用等。随着分子生物学、细胞生物学、材料学以及制剂技术的发展 ,使得脂质体在现代药剂学的制剂研究中得到广泛的应用 ,出现了不同给药系统的脂质体靶向制剂。从目前的文献报道可知 ,脂质体不同给药途径大体可分为胃肠道和非胃肠道两种。本文将从特点、作用机理、稳定性、转运途径等几个方面对近年来有关脂质体不同给药系统的研究进展作一综述。1 脂…     

重组人生长激素脂质体的制备及载药研究

目的采用乙醇注入法结合反复冻融技术制备重组人生长激素脂质体,并考察影响包封率的主要因素。方法采用乙醇注入法制备空白脂质体,并通过反复冻融载药,采用葡聚糖凝胶柱分离结合CBB G-250染色法测定游离药物含量,计算包封率;考察孵化时间、孵化温度、冻融次数对包封率的影响;对冻干制品的外观、复溶速度、粒径及分布进行综合评分,优选冻干支持剂。结果孵化时间为40 min、孵化温度为10℃、冻融次数为3次时,能够获得较高包封率的脂质体,包封率为63.59%。海藻糖在脂质体冷冻干燥过程中具有最好的保护作用。结论乙醇注入法结合反复冻融可用于大分子蛋白质类脂质体的制备。     

丹参酮前体脂质体的研制

目的：研究丹参酮前体脂质体的制备方法、含量测定及其性质。方法：以正交试验设计筛选丹参酮脂质体混悬液的处方，采用冷冻干燥法制备前体脂质体；以紫外分光光度法进行含量测定。结果：丹参酮脂质体混悬液的优选处方质量比为：蛋磷脂：胆固醇=2：1，蛋磷脂：吐温-80：4：1，丹参酮：蛋磷脂=1：20；水合介质为注射用水。冻干品水合重建后的平均粒径为270nm，包封率达80％。冻干品室温放置6个月，稳定性良好，粒径和包封率基本无变化。体外试验未发现该脂质体有溶血毒性。结论：该方法制得的丹参酮前体脂质体体外质量基本符合药典要求。     

饱和磷脂脂质体的室温下制备及其性质的研究

目的考察室温下用饱和磷脂制备脂质体的新方法(加入特殊的附加剂)及其对以蛋白多肽类为主药的包封情况,并研究了脂质体的体外性质。方法通过加入特殊的附加剂,用反相蒸发-超声分散法制备脂质体,并初步考察了其室温放置的稳定性;以尿激酶为例,考察所得脂质体的粒度分布和形态;对不同的蛋白多肽类药物进行包封;以阿霉素为模型药物,考察脂质体在PBS和小牛血清中的泄漏。结果附加剂DSPE-PEG 2000只需1%的用量(占磷脂的摩尔比),即可用饱和磷脂在室温下超声1 min制得脂质体;所得脂质体平均粒径在100 nm以下,形态圆整,室温放置稳定;对胰岛素和水蛭素的包封率与普通脂质体相近(23%),对尿激酶包封率高达(65.4±2.6)%;体外泄漏缓慢。结论提出的制备方法条件温和,产品稳定性好,非常适合高分子量蛋白类药物,并可获得较高的包封率,是一种很有前景的脂质体制备方法。     

鲑鱼降钙素柔性脂质体大鼠鼻腔给药的降血钙效应

本文采用薄膜分散-超声挤压过膜法制备鲑鱼降钙素柔性脂质体，对其形态学及粒径进行了考察。以大鼠为实验动物，鼻腔给药，采用OCPC比色法测定大鼠血清钙离子浓度，计算降血钙百分率F%和降血钙效应D%，与鲑鱼降钙素普通脂质体、鲑鱼降钙素水溶液比较，以此评价鲑鱼降钙素柔性脂质体经大鼠鼻腔给药后的降血钙效应和附加剂对降钙素柔性脂质体的降血钙效应的影响。另外还对柔性脂质体的纤毛毒性进行考察。结果表明鲑鱼降钙素水溶液仅轻微降低血钙浓度，鲑鱼降钙素普通脂质体能提高降血钙效果，鲑鱼降钙素柔性脂质体呈现了最强的降血钙效果，其降血钙效果与脂质体中附加的表面活性剂的用量和种类相关，用去氧胆酸钠修饰的脂质体的降血钙效果最好，并且附加的表面活性剂用量越高，降血钙效果越强。柔性脂质体可以显著地降低去氧胆酸钠的纤毛毒性。结果显示，柔性纳米脂质体能显著提高降钙素经鼻腔给药的降血钙效果，柔性脂质体是蛋白多肽类药物鼻腔给药的一种有效的载体。     

Development and evaluation of inhalational liposomal system of budesonide for better management of asthma

Budesonide is a corticosteroid used by inhalation in the prophylactic management of asthma. However, frequent dosing and adverse effects (local and systemic) remain a major concern in the use of budesonide. Liposomal systems for sustained pulmonary drug delivery have been particularly attractive because of their compatibility with lung surfactant components. In the present investigation, pulmonary liposomal delivery system of budesonide was prepared by film hydration method and evaluated for sustained release. Various parameters were optimized with respect to entrapment efficiency as well as particle size of budesonide liposomes. For better shelf life of budesonide liposomes, they were freeze dried using trehalose as cryoprotectant. The liposomes were characterized for entrapment efficiency, particle size, and surface topography; in vitro drug release was evaluated out in simulated lung fluid at 37° at pH 7.4. The respirable or fine particle fraction was determined by using twin stage impinger. The stability study of freeze dried as well as aqueous liposomal systems was carried out at 2-8° and at ambient temperature (28±40). The freeze dried liposomes showed better fine particle fraction and drug content over the period of six months at ambient as well as at 2-8° storage condition compared to aqueous dispersion of liposomes.     

The choice of a suitable oligosaccharide to prevent aggregation of PEGylated nanoparticles during freeze thawing and freeze drying

In a previous study we have shown that the oligosaccharide inulin can prevent aggregation of poly(ethylene glycol) (PEG) coated plasmid DNA/cationic liposome complexes ("PEGylated lipoplexes") during freeze thawing and freeze drying [Hinrichs et al., 2005. J. Control. Release 103, 465]. By contrast, dextran clearly failed as stabilizer. These results were ascribed to the fact that inulin and PEG are compatible while dextran and PEG are not. In this study the stabilizing capacities of inulin and dextran (of various molecular weights) during freeze thawing and freeze drying of four different types of nanoparticles, each type with different amounts of PEG at their surface, were investigated. Freeze drying and freeze thawing of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/dioleoyl-phosphatidyl-ethanolamine (DOPE) liposomes and egg phosphatidyl choline (EPC)/cholesterol (CHOL) liposomes showed that inulins are excellent stabilizers even for highly PEGylated liposomes while (especially higher molecular weight) dextrans dramatically lost their stabilizing capacity when increasing the degree of PEGylation of the liposomes. The same results were obtained for plasmid DNA/DOTAP/DOPE complexes. Finally, both inulin and dextran could prevent full aggregation of plasmid DNA/polyethylenimine (PEI) complexes independent whether PEI was PEGylated or not. It is concluded that inulins are preferred as stabilizers over dextrans for various types of PEGylated nanoparticles due to their compatibility with PEG.     

Factors affecting the size distribution of liposomes produced by freeze-thaw extrusion.

This paper describes the development of a protocol for the production of liposomes using a freeze-thaw extrusion methodology. Laser diffraction particle size analysis showed that the median diameter of freeze-thawed egg phosphatidylcholine multilamellar vesicles (eggPC MLVs) was increased when cholesterol was included in the bilayers. Using a freeze-thaw cycle of 3 min freezing in liquid nitrogen at -196 degrees C followed by 3 min thawing at 50 degrees C resulted in an anomalously large particle size for eggPC/cholesterol formulations. When liposomes were repeatedly freeze-thawed a maximum size was achieved after five freeze-thaw cycles. Dispersion of liposomes in sodium chloride solutions promoted size increases following freeze-thawing, suggesting that vesicles had aggregated or fused. Poloxamers P338 and P407 inhibited the size increases observed during freeze-thawing for eggPC MLVs dispersed in 1.0 M NaCl, probably through steric prevention of aggregation and fusion.     

Inhalational System for Etoposide Liposomes: Formulation Development and In Vitro Deposition

Etoposide is a semisynthetic compound, widely used in treatment of non small cell lung cancer. However, frequent dosing and adverse effects remain a major concern in the use of etoposide. Liposomal systems for pulmonary drug delivery have been particularly attractive because of their compatibility with lung surfactant components. In the present investigation, pulmonary liposomal delivery system of etoposide was prepared by film hydration method. Various parameters were optimized with respect to entrapment efficiency as well as particle size of etoposide liposomes. For better shelf life of etoposide liposomes, freeze drying using trehalose as cryoprotectant was carried out. The liposomes were characterized for entrapment efficiency, particle size, surface topography, and in vitro drug release was carried out in simulated lung fluid at 37° at pH 7.4. The respirable or fine particle fraction was determined by using twin stage impinger. The stability study of freeze dried as well as aqueous liposomal systems was carried out at 2-8° and at ambient temperature (28±4°). The freeze dried liposomes showed better fine particle fraction and drug content over the period of six months at ambient as well as at 2-8° storage condition compared to aqueous dispersion of liposomes.     

叔丁醇-水共溶剂体系冻干脂质体

目的考察用叔丁醇水共溶剂体系冻干脂质体的可行性。方法以钙黄绿素脂质体为模型,考察了糖脂比、磷脂组成以及叔丁醇含量对钙黄绿素滞留率的影响。采用LS230粒度分析仪对冻干前后脂质体的粒径进行了测定。采用DSC分析和低温显微技术考察了样品的冻结行为。通过绘制升华曲线,确定叔丁醇的存在是否可以缩短冻干周期。结果与结论用叔丁醇水共溶剂体系冻干脂质体,最好使用HSPC脂质体。冻干前后,钙黄绿素在HSPC脂质体中的滞留率和以水为溶剂冻干脂质体时基本相同,并且脂质体的粒径没有显著变化。叔丁醇的存在可以加快升华速度,缩短冻干周期。     

Uptake characteristics of liposomes by rat alveolar macrophages: influence of particle size and surface mannose modification

The influence of particle size and surface mannose modification on the uptake of liposomes by alveolar macrophages (AMs) was investigated in-vitro and in-vivo. Non-modified liposomes of five different particle sizes (100, 200, 400, 1000 and 2000 nm) and mannosylated liposomes with 4-aminophenyl-alpha-D-mannopyranoside (particle size 1000 nm) were prepared, and the uptake characteristics by rat AMs in-vitro and in-vivo were examined. The uptake of non-modified liposomes by rat AMs in-vitro increased with an increase in particle size over the range of 100-1000 nm, and became constant at over 1000 nm. The uptake of non-modified liposomes by AMs after pulmonary administration to rats in-vivo increased with an increase in particle size in the range 100-2000 nm. The uptake of mannosylated liposomes (particle size 1000 nm) by rat AMs both in-vitro and in-vivo was significantly greater than that of non-modified liposomes (particle size 1000 nm). The results indicate that the uptake of liposomes by rat AMs is dependent on particle size and is increased by surface mannose modification.     

布洛芬HPMC骨架片药物释放因素研究

目的 考察影响布洛芬亲水性骨架片体外释药的各种因素。方法 以羟丙基甲基纤维素（HPMC）为骨架材料，用湿法制粒和粉末直接压片法制备缓释骨架片，并考察HPMC用量，粒度，制备方法，片子大小及其它辅料对布洛芬HPMC骨架片的体外释药的影响。结果 布洛芬HPMC骨架片的体外释药均符合Higuchi方程。HPMC的用量，粒度和制法，片子大小对布洛芬的释放速率均有显著影响。湿法制片的释药速率比干法慢。布洛共姝释药速率随HPMC粒度的减小和片子的增大而减慢。淀粉，PVP、MCC、EC的加入（每片HPMC的含量不变）均减慢布洛芬释药速率。结论 HPMC用量、粒度、制备方法、片子大小及其它辅料为布洛芬骨架片释放速率的主要因素。     

吲哚拉辛HPMC骨架片药物释放因素研究

目的 考察影响吲哚拉辛亲水性骨架片体外释药的各种因素。方法 以羟丙基甲基纤维素（HPMC）为骨架材料,用湿法制粒和粉末直接压片法制备缓释骨架片,并考察HPMC用量、粒度、制备方法、片子大小及其它辅料对吲哚拉辛HPMC骨架片的体外释药的影响。结果 吲哚拉辛HPMC骨架片的体外释药均符合Higuchi方程。HPMC的用量,粒度和制法,片子大小对吲哚拉辛的释放速率随HPMC粒度和片子的减小而减慢。淀粉、PVP、MCC的加入（每片HPMC的含量不变）均加快吲哚拉辛释药速率,且加入量不同,其释药速率问具有显著性差异。随着EC加入量的增加（≥40mg。片^-1）．吲哚拉辛释放速率显著加快。结论 HPMC用量和粒度、制备方法、片子大小及其它辅料为影响吲哚拉辛骨架片释放速率主要因素。