Stabilized tetraether lipids based particles guided prophyrins photodynamic therapy

Photodynamic therapy (PDT) that involves ergonomically delivered light in the presence of archetypical photosensitizer such as Protoporphyrin IX (PpIX) is a time-honored missile strategy in cancer therapeutics. Yet, the premature release of PpIX is one of the most abundant dilemma encounters the therapeutic outcomes of PDT due to associated toxicity and redistribution to serum proteins. In this study, ultrastable tetraether lipids (TELs) based liposomes were developed. PpIX molecules were identified to reside physically in the monolayer; thereby the inherent π-π stacking that leads to aggregation of PpIX in aqueous milieu was dramatically improved. TEL_29.9?mol% and TEL_62mol% based liposomes revealed PpIX sustained release diffusion pattern from spherical particles as confirmed by converged fitting to Baker &; Lonsdale model. Stability in presence of human serum albumins, a key element for PDT accomplishment was emphasized. The epitome candidates were selected for vascular photodynamic (vPDT) in in-Ovo chick chorioallantoic membrane. Profoundly, TEL_62mol% based liposomes proved to be the most effective liposomes that demonstrated localized effect within the irradiated area without eliciting quiescent vasculatures damages. Cellular photodynamic therapy (cPDT) revealed that various radiant exposure doses of 134, 202, 403 or 672?mJ.cm^?2 could deliberately modulate the photo-responses of PpIX in TEL-liposomes.     

Co-delivery of a CD4 T cell helper epitope via covalent liposome attachment with a surface-arrayed B cell target antigen fosters higher affinity antibody responses

Liposomal vaccines incorporating adjuvant and CD4 T cell helper peptides enhance antibody responses against weakly immunogenic B cell epitopes such as found in the membrane proximal external region (MPER) of the HIV-1 gp41 subunit. While the inclusion of exogenous helper peptides in vaccine formulations facilitates stronger and more durable antibody responses, the helper peptide incorporation strategy per se may influence the overall magnitude and quality of B cell target antigen immunogenicity. Both variability in individual peptide encapsulation as well as the potential for liposome surface-associated helper peptides to misdirect the humoral response are potential parameters impacting outcome. In this study, we used MPER/liposome vaccines as a model system to examine how the mode of the potent LACK T helper peptide formulation modulates antibody responses against the MPER antigen. We directly compared liposome surface-arrayed palmitoyl LACK (pLACK) versus soluble LACK (sLACK) encapsulated in the liposomes and free in solution. Independent of LACK formulation methods, dendritic cell activation and LACK presentation were equivalent in vivo. The frequency of MPER-specific GC B cells promoted by sLACK was higher than that stimulated by pLACK formulation, a finding associated with a significantly greater frequency of LACK-specific GC B cells induced by pLACK. While there were no significant differences in the quantity of MPER-specific serological responses, the MPER-specific antibody titer trended higher with sLACK formulated vaccines at the lower dose of LACK. However, pLACK generated relatively greater MPER-specific antibody affinities than those induced by sLACK-formulated vaccines. Overall, the results suggest that liposomal surface-associated LACK enhances immunogenicity of LACK through better engagement of LACK-specific B cells. Of note, this is not detrimental to the induction of MPER-specific immune responses; rather, the elicitation of higher affinity anti-MPER antibodies benefits from augmented help delivered via covalent linkage of the pLACK CD4 T cell epitope in conjunction with MPER/liposome presentation.     

氯膦酸二钠脂质体清除巨噬细胞对小鼠造血干祖细胞归巢过程的影响

目的 探讨清除巨噬细胞对小鼠造血干祖细胞（hematopoietic stem/progenitor cells,HSPC）归巢过程的影响。 方法 免疫磁珠分选获得小鼠HSPC,使用羧基荧光素二醋酸盐琥珀酰亚胺酯（Carboxyfluorescein diacetate succinimide ester,CSFE）染色标记,采用氯膦酸二钠脂质体（clodronate liposomes,Clod）方法建立去除巨噬细胞的小鼠模型,通过流式细胞术检测HSPC移植的归巢效率,通过实时荧光定量逆转录酶链式反应方法和酶联免疫吸附测定方法检测去除巨噬细胞后骨髓微环境中CXCL12、SCF和人血管内皮细胞粘附分子1(vascular adhesion molecule 1,VCAM1)分子mRNA表达水平和蛋白表达水平的变化。 结果 氯膦酸二钠脂质体作用后第24小时和第48小时,小鼠骨髓中CD11b+F4/80+巨噬细胞数量显著减少（P＜0.05）;移植小鼠HSPC后,相较于对照组,去除巨噬细胞组小鼠HSPC归巢效率显著降低（P＜0.05）;同时去除巨噬细胞组小鼠骨髓微环境中CXCL12、SCF的mRNA和蛋白表达量比对照组显著降低（P＜0.05）,而VCAM1表达量无显著变化。 结论 去除巨噬细胞能够显著降低小鼠HSPC归巢效率,该作用可能与去除巨噬细胞后导致的骨髓微环境中CXCL12与SCF含量减少有关。     

具有线粒体靶向性的雷公藤甲素TPP-PEG-PCL脂质体的制备及其促肝肿瘤细胞凋亡研究

目的 成功制备雷公藤甲素（3-丙羧基）三苯基溴化膦（TPP）-聚乙二醇-b-聚己内脂（PEG-PCL）脂质体（Tr@TPP/Lip）,评价其靶向性及促肝肿瘤细胞凋亡效果。方法 采用正交试验优选Tr@TPP/Lip的制备工艺,再研究该载药系统的粒径、Zeta电位、载药量、包封率和多分散系数及透射电镜微观形态,评价Tr@TPP/Lip的稳定性、溶血性、释放情况;采用荧光试验,研究脂质体与肝肿瘤细胞的融合情况、线粒体靶向性和肝脏靶向性;在等剂量给药条件下,评价Tr@TPP/Lip促肝癌细胞凋亡效果。结果 正交试验优选的Tr@TPP/Lip粒径为（113.5±17.6）nm,Zeta电位（12.6±0.7）mV,包封率为（71.3±3.2）%,载药量为（3.9±1.1）%,多分散系数为0.12±0.04;透射电子显微镜图片显示Tr@TPP/Lip呈规则圆球形,该脂质体稳定性良好,具有较小的溶血率和良好的缓释药物性能;荧光试验结果显示,TPP阳离子能促进脂质体与肿瘤细胞的融合,并靶向线粒体,还能提高药物在肝肿瘤部位的靶向和滞留效果;细胞药效结果显示,Tr@TPP/Lip具有良好的促肝肿瘤细胞凋亡效果,能明显降低线粒体膜Zeta电位、增加细胞内活性氧水平和Caspase-3的释放,显著增加促凋亡蛋白Bcl-2、减少抗凋亡Bax蛋白的表达,这些细胞凋亡试验结果均明显优于雷公藤甲素普通脂质体和雷公藤甲素。结论 Tr@TPP/Lip具有较好的线粒体靶向功能,能增强药物促肝肿瘤细胞凋亡效果。     

P167肽修饰的多柔比星长循环脂质体在大鼠体内的药动学和药效学

目的研究P167肽修饰对多柔比星脂质体大鼠静脉给药的体内药动学和药效学的影响。方法通过pH梯度法分别制备多柔比星长循环脂质体（DOX—SSL）和P167肽修饰的多柔比星长循环脂质体（DOX—P167一SSL）。12只sD大鼠随机分为2组,分另q尾静脉注射DOX．SSL和DOX—P167-SSL,给药剂量为2．5mg·kg-1。采用HPLC内标法测定不同给药时间的血清多柔比星浓度,用WinNonlin软件拟合并计算药动学参数。制备大鼠脑胶质瘤模型,经核磁扫描测定肿瘤体积,均匀分组,分别尾静脉注射生理盐水、DOX—SSL和DOX．P167．SSL,每组6只动物,给药剂量为2．5mg·kg-1,3d给药1次,共给药5次。以相对肿瘤增殖率（T／C％）为指标评价药效。结果DOX—SSL和DOX—P167-SSL大鼠尾静脉给药后,均符合二室模型。DOX—P167-SSL组的tl／,t1/2及AUC分别为4．89min、837．57rain、610．35min·mg·L-1,均低于DOX—SSL组的16．23、2940．48和1301．16min·mg·L-1。DOX—P167-SSL组T／C％为7．32％,而DOX—SSL组为37．07％。结论P167肽的修饰使多柔比星长循环脂质体的长循环效果降低,但药效得到明显提高,这可能与P167肽的穿透作用有关。     

盐酸小檗碱脂质体的制备及其含量、包封率的测定

目的：制备盐酸小檗碱脂质体,并测定其包封率和脂质体各成分含量。方法：采用硫酸铵梯度法制备盐酸小檗碱脂质体,以超速离心法、微柱法、超滤法对盐酸小檗碱脂质体包封率的测定方法进行研究,以HPLC-ELSD测定脂质体各成分含量。结果：超速离心法能将未包封药物与脂质体很好地分离,最佳超速离心条件：离心速度为60000 r·min-1,离心时间为1 h,离心温度为10℃,脂质浓度为6 mg·ml-1。结论：包封率测定方法具有简单、快速分离等优点。 HPLC-ELSD能够同时测定脂质体各成分含量。     

紫杉醇热敏脂质体的制备与质量控制

目的：制备紫杉醇热敏脂质体,建立测定其含量、有关物质及溶血磷脂的方法,考察其含量、有关物质、溶血磷脂量以及体外溶血性。方法采用高效液相色谱（ HPLC）-紫外法检测制剂含量及有关物质,HPLC-电雾式检测器检测制剂中溶血磷脂单棕榈酰磷脂酰胆碱的量,并对检测方法进行验证;分光光度法测定体外溶血百分率。结果紫杉醇在60.39~181.17μg·mL-1范围内峰面积与浓度线性关系良好,回收率及精密度实验均符合要求;有关物质测定方法专属性、灵敏度和系统适用性均符合要求;溶血磷脂测定方法的专属性和灵敏度符合有关规定,在1.5~50.0μg·mL-1范围内峰面积与浓度线性关系良好,回收率、重复性均符合要求;3批自制紫杉醇热敏脂质体的含量在90.0%~110.0%之间,单个杂质含量均〈0.5%,总杂质含量均〈2.0%,体外基本不引起溶血。结论含量、有关物质及溶血磷脂检测方法均可用于紫杉醇热敏脂质体的质量评价,自制紫杉醇热敏脂质体各项指标均符合要求,且质量稳定。     

正交试验优选哈西奈德脂质体制备工艺

目的优选哈西奈德脂质体的最佳制备工艺。方法以胆固醇、卵磷脂为载体,采用薄膜分散法制备哈西奈德脂质体,以包封率为评价指标,采用正交试验进行系统研究,筛选哈西奈德脂质体的最佳制备工艺。结果哈西奈德脂质体的最佳制备工艺为：卵磷脂与胆固醇质量之比为6：1,氯仿与甲醇体积之比为1：1,水化温度为60℃,磷酸盐缓冲液的pH为6．5。优化后制备3批脂质体,平均包封率为93．29％±0．77％,粒径范围为98．26～102．54nm。结论选工艺制备的脂质体包封率高,粒径较均匀,形态较好,结构完整,该方法简单可行。     

包合物脂质体靶向系统在给药中的应用

近年来,包合物和脂质体作为药物的载体被广泛用于药物制剂领域,各自发挥着自身的优势。将环糊精包合物应用于脂质体给药系统——这一新型的药物载体,能够更好地提高靶向给药效果。本文通过概述包合物及脂质体的优势,阐明包合物脂质体这一新型给药系统能提高药物的载药量,增加脂质体的稳定性,对提高药物的吸收和临床疗效等方面具有重要意义,对于靶向给药系统的进一步发展具有新的参考价值。     

甘草次酸修饰姜黄素阳离子脂质体对肿瘤Walker256细胞的影响

目的：研究姜黄素及甘草次酸修饰姜黄素阳离子脂质体对Walker256细胞的影响。方法：不同浓度姜黄素与甘草次酸修饰姜黄素阳离子脂质体处理Walker256细胞后,采用CCK-8法检测细胞增殖抑制率;用流式细胞仪检测细胞吸收、细胞周期变化情况;Annexin V/PI双染法检测细胞凋亡;Western blot检测Wnt及β-catenin表达水平。结果：姜黄素和甘草次酸修饰姜黄素阳离子脂质体对肿瘤细胞Walker256均具有明显的抑制作用。与游离姜黄素相比,甘草次酸修饰姜黄素阳离子脂质体明显增强细胞对姜黄素的吸收,显著增强对Walker256细胞的增殖抑制、凋亡、细胞周期G2期的阻滞作用,明显下调Wnt及β-catenin的表达。结论：甘草次酸修饰姜黄素阳离子脂质体比游离姜黄素具有更强的抗肿瘤Walker256细胞的作用。