阿霉素-五味子乙素pH敏感聚合物胶束的制备与制剂学性质

目的以p H敏感聚合物聚乙二醇-聚乳酸-聚组氨酸[poly(ethyleneglyco1)-poly(D,L-lactide)-poly(L-histidine),m PEG-PLA-PHis]胶束为载体,联合包载抗肿瘤药物阿霉素与多药耐药逆转剂五味子乙素制备聚合物胶束,并对其制剂学性质进行研究。方法采用薄膜分散法制备阿霉素-五味子乙素p H敏感聚合物胶束,以包封率、载药量和稳定性(载药胶束24 h的包封率和载药量变化)为评价指标,采用单因素试验及Box-Behnken效应面法筛选最优处方;应用透射电子显微镜观察载药胶束的外观形态,动态光散射法测定载药胶束的粒径及zeta电位;透析法考察载药胶束在不同p H条件下的释药行为。结果制备的阿霉素-五味子乙素p H敏感聚合物胶束平均粒径为64.73 nm,zeta电位为-8.7 m V。最优处方中阿霉素包封率为95.3%,载药量为8.7%,五味子乙素包封率为76.1%,载药量为3.4%,载药胶束稳定性较好。体外释放结果表明,所制备的阿霉素-五味子乙素p H敏感聚合物胶束在弱酸性条件下,药物释放速率明显加快。结论采用星点设计-效应面法优化处方与制备工艺,所制备的阿霉素-五味子乙素p H敏感聚合物胶束粒径分布均匀,包封率和载药量良好,具有明显的p H响应行为。     

水溶性紫杉醇前药的制备及抗肿瘤活性的研究

目的紫杉醇是具有良好抗肿瘤疗效的化学药物,由于紫杉醇本身化学结构复杂,难溶于水,在一定程度上限制了紫杉醇药物在临床上的广泛应用,因此改善紫杉醇水溶性是解决紫杉醇药物不足的关键问题。方法本实验选用水溶性叶酸配体作为"导向基团",谷氨酸为连接叶酸和紫杉醇的Linker,氨基PEG(MW:350)为药物增溶剂和稳定剂,制备水溶性叶酸-PEG-谷氨酸-紫杉醇前药。用LC-MS鉴定前药的化学结构,通过对前药溶解性及释药动力学曲线的测定,确定前药的理化性质。用MTT实验分析并对比紫杉醇原药与前药在不同肿瘤细胞(MCF-7、MDA-MB-231、A549)和正常细胞HELF(人胚肺成纤维细胞)中的毒性和药效作用。用荧光标记法直观观察紫杉醇前药在肿瘤细胞和组织中的靶向性。结果实验结果证明已成功合成叶酸-PEG-谷氨酸-紫杉醇前药,并具有较好的溶解性和原药释放动力学曲线,细胞实验表明在叶酸受体-配体作用的介导下,叶酸-PEG-谷氨酸-紫杉醇前药靶向叶酸受体高表达的肿瘤细胞,减少对叶酸受体低表达正常细胞的毒副作用。结论叶酸-PEG-谷氨酸-紫杉醇前药具有良好的抗肿瘤活性。     

可拮抗血清快速胞吞的K5多糖-阿霉素前体药物及其体外评价

目的:本研究利用肝素前体K5多糖连接抗肿瘤药物阿霉素(doxorubicin,DOX)制备具有p H敏感特性的K5多糖-阿霉素前体药物(K5-DOX),并在体外对其理化性质和活性进行评价。方法:通过希夫碱反应制备K5-DOX,对DOX负载量、K5-DOX在溶液中的形貌和体外药物释放等性质进行了考察。通过人宫颈癌He La细胞对其体外细胞摄取和细胞毒性进行评价。结果:成功制备K5-DOX,DOX含量为17.4%。药物释放研究发现,K5-DOX在p H 5.0酸性条件下DOX的释放速率远高于生理p H 7.4时DOX的释放速率,具有p H响应性。纳米粒子表面带负电荷,在含10%胎牛血清(FBS)溶液中表现出可拮抗血清的优良特性。细胞摄取结果表明,K5-DOX可迅速被细胞摄取,且其细胞摄取率远高于游离阿霉素。体外细胞毒性结果表明,K5-DOX具有良好的抗肿瘤活性。结论:结果表明,K5-DOX是一种具有潜在应用价值的抗肿瘤前体药物,K5多糖有望成为新一代药物载体。     

pH敏感多肽修饰载紫杉醇脂质体的制备及评价

目的制备p H敏感多肽修饰载紫杉醇脂质体(p HS-LP-PTX),并评价其体外性质。方法采用薄膜分散法制备PHS-LP-PTX,MTT实验考察脂质体对MCF-7细胞和Hep G2细胞的毒性,通过细胞摄取实验考察脂质体与肿瘤细胞的结合能力。结果所制备的p HS-LP-PTX在p H6.4时平均粒径为125.5±13.4 nm,Zeta电位为10.47±2.53 m V,24 h内具有良好的血清稳定性。MTT结果显示:p H6.4时,p HS-LP-PTX的细胞毒性优于各对照组。体外细胞摄取实验表明:p H6.4时,MCF-7细胞和Hep G2细胞对p HS-LP-PTX的摄取效率优于p H7.4时和普通脂质体。结论紫杉醇脂质体经过p H敏感多肽修饰后,能增强脂质体在酸性环境下的细胞穿透能力,是一种良好的p H敏感型肿瘤靶向给药系统。     

紫杉醇pH敏感嵌段共聚物胶束的制备与体外评价

目的应用pH敏感聚组氨酸-聚乳酸-聚乙二醇(poly(L-histidine)-poly(D,L-lactide)-poly(ethylene glycol),PHis-PLA-mPEG)聚合物为载体材料,采用溶剂挥发法制备紫杉醇pH敏感嵌段共聚物胶束,并对其体外性质进行评价。方法采用芘荧光探针法测定PHis-PLA-mPEG聚合物的临界胶束浓度(critical micelle concentration,CMC);超速离心法测定紫杉醇共聚物胶束的包封率和载药量;分别利用动态光散射法和Zeta电位分析仪对胶束的粒径分布和表面电位进行测定;采用透析法测定载药胶束在不同pH条件下的体外释药行为。结果 PHis-PLA-mPEG临界胶束质量浓度为8.9 mg·L-1,胶束载药量质量分数为8%;包封率可达90%以上;载药胶束的平均粒径为150.2nm,PDI为0.097,粒度分布较窄,Zeta电位为-14.3 mV;载药胶束在弱酸性条件下,药物释放行为明显加快。结论 PHis-PLA-mPEG聚合物载体材料具有较好的pH敏感释药行为,其作为抗肿瘤药物的靶向传递系统具有较好的应用前景。     

载阿霉素的单壁碳纳米管的制备及体外抗肿瘤初步评价

目的 为了开发一种新型的多功能药物递送载体平台，引入了具有较强细胞摄取能力和较高载药效率的碳纳米管，通过功能化修饰可能降低碳纳米管细胞毒性的同时提高肿瘤细胞对其的摄取能力。方法 选取单壁碳纳米管(single-walled carbon nanotubes, SWCNTs),通过混酸处理、活性基团以及靶向基团的修饰降低载体材料的毒性，提升其生物相容性，并且为载体材料增加了对肿瘤细胞的靶向性，以X-射线光电子能谱(X-ray photoelectron spectroscopy, XPS),X射线衍射(X-ray diffraction, XRD)等分析手段验证了修饰基团的成功连接。借助MTT实验以及荧光图像检测了载体的细胞毒性，摄取能力和活性氧水平。结果 经聚乙二醇(polyethylene glycol, PEG),聚乙烯亚胺(polyetherimide, PEI),叶酸(folicacid, FA)等活性基团修饰后的SWCNTs细胞毒性明显下降，且增加了MCF-7细胞对阿霉素(doxorubicin, DOX)的有效摄取和ROS水平，提高了机体抗肿瘤免疫能力。结论 表明修饰后的S...     

聚合胶束载药多柔比星的研究进展

多柔比星（阿霉素，adriamycin）是临床上广泛使用的抗癌药，但其对正常组织的毒性和固有的多药耐药性是急需解决的问题。聚合胶束作为抗癌药的载体具有靶向作用，可减少毒副作用，提高抗癌药物的化疗指数。现对国外聚合胶束载药阿霉素的制备、理化性质、体外释放、生物学分布、抗肿瘤活性及靶向性进行综述。     

叶酸聚合物胶束给药系统制备及其评价

将叶酸-聚乙二醇-二硬脂酰磷脂酰乙醇胺(FA-PEG-DSPE)与甲氧基聚乙二醇-二硬脂酰磷脂酰乙醇胺(MPEG-DSPE)的混合物(摩尔比1:100)作为载体材料,采用成膜水化法,分别制成载疏水性抗肿瘤药物9-硝基喜树碱及紫杉醇的聚合物胶束.体外抗HeLa和SGC7901肿瘤细胞活性的试验表明,叶酸修饰的聚合物胶束能提高难溶性抗肿瘤药物体外抗肿瘤细胞活性.     

透明质酸修饰的PAMAM纳米胶束的制备及性质研究

目的采用透明质酸(HA)修饰聚酰胺-胺(PAMAM)树状大分子,以姜黄素、阿霉素为模型药物,构建HA-PAMAM纳米胶束肿瘤主动靶向给药系统。方法采用酰胺化反应合成不同透明质酸取代度的HA-PAMAM;采用溶剂挥发法制备HA-PAMAM单药和双药联合载药胶束;采用高效液相色谱法测定姜黄素、阿霉素的包封率和载药量;通过体外透析法研究载药胶束的释药特性。结果采用溶剂挥发法制备阿霉素、姜黄素单药或联合载药胶束,载药胶束的包封率与载药量较高(姜黄素分别为66.70%、6.57%,阿霉素分别为82.14%、33.15%)。HA-PAMAM载药胶束体外释放显示出良好的缓释性能。结论透明质酸修饰的PAMAM是一种具有良好肿瘤靶向性应用前景的纳米载药系统。     

Paclitaxel Prodrugs with Sustained Release and High Solubility in Poly(ethylene glycol)-b-poly(ε-caprolactone) Micelle Nanocarriers: Pharmacokinetic Disposition, Tolerability, and Cytotoxicity

Purpose

Develop a Cremophor® and solvent free formulation of paclitaxel using amphiphilic block co-polymer micelles of poly(ethylene glycol)-b-poly(?-caprolactone) (PEG-b-PCL) and characterize their release, solubility, cytotoxicity, tolerability, and disposition.

Methods

Hydrophobic prodrugs of paclitaxel were synthesized via DCC/DMAP or anhydride chemistry to overcome the poor loading (<1% w/w) of paclitaxel in micelles of PEG-b-PCL. Micelles were prepared by a co-solvent extraction technique. A micellar formulation of paclitaxel prodrug (PAX7′C₆) was dosed intravenously to rats (10 mg/kg) and compared to Taxol® (paclitaxel in CrEL:EtOH) and PAX7′C₆ in CrEL:EtOH as controls at the same dose. Pharmacokinetic parameters and tissue distribution were assessed.

Results

Paclitaxel prodrugs had solubilities >5 mg/ml in PEG-b-PCL micelles. Resulting PEG-b-PCL micelles contained 17-22% w/w prodrug and were less than 50 nm in diameter. PEG-b-PCL micelles released paclitaxel prodrugs over several days, t_1/2>3 d. Only the 7′derivative of paclitaxel with the shortest acylchain 7′hexonoate (PAX7′C₆) maintained cytotoxic activity similar to unmodified paclitaxel. PAX7′C₆ micelles demonstrated an increase in area under the curve, half-life, and mean residence time while total clearance and volume of distribution decreased.

Conclusions

Paclitaxel prodrugs in PEG-b-PCL micelle nanocarriers augment the disposition and increase tolerability making further studies on tumor efficacy warranted.     

Pure redox-sensitive paclitaxel–maleimide prodrug nanoparticles: Endogenous albumin-induced size switching and improved antitumor efficiency

A commercial albumin-bound paclitaxel nano-formulation has been considered a gold standard against breast cancer. However, its application still restricted unfavorable pharmacokinetics and the immunogenicity of exogenous albumin carrier. Herein, we report an albumin-bound tumor redox-responsive paclitaxel prodrugs nano-delivery strategy. Using diverse linkages (thioether bond and disulfide bond), paclitaxel (PTX) was conjugated with an albumin-binding maleimide (MAL) functional group. These pure PTX prodrugs could self-assemble to form uniform and spherical nanoparticles (NPs) in aqueous solution without any excipients. By immediately binding to blood circulating albumin after intravenous administration, NPs are rapidly disintegrated into small prodrug/albumin nanoaggregates in vivo, facilitating PTX prodrugs accumulation in the tumor region via albumin receptor-mediated active targeting. The tumor redox dual-responsive drug release property of prodrugs improves the selectivity of cytotoxicity between normal and cancer cells. Moreover, disulfide bond-containing prodrug/albumin nanoaggregates exhibit long circulation time and superior antitumor efficacy in vivo. This simple and facile strategy integrates the biomimetic characteristic of albumin, tumor redox-responsive on-demand drug release, and provides new opportunities for the development of the high-efficiency antitumor nanomedicines.KEY WORDS: Paclitaxel, Abraxane, Redox-sensitive, Disulfide bond, Maleimide, Prodrug-based nano-drug delivery systems, Prodrug/albumin nanoaggregates, Breast cancer treatment     

Folate-modified poly(2-ethyl-2-oxazoline) as hydrophilic corona in polymeric micelles for enhanced intracellular doxorubicin delivery

The transmembrane transport of drug loaded micelles to intracellular compartment is quite crucial for efficient drug delivery. In the current study, we investigated the cellular internalization and anticancer activity of doxorubicin loaded micelles with folate modified stealthy PEOz corona. Folate-decorated micelles incorporating doxorubicin were characterized for particle size, degree of folate decoration, drug loading content and encapsulation efficiency, morphology, and surface charge. The targeting capability and cell viability were assessed using HeLa, KB, A549 and MCF-7/ADR cell lines. In vitro study clearly illustrated the folate receptor (FR) mediated targeting of FA modified micelles to FR-positive human HeLa, KB and MCF-7/ADR cells, while specific delivery to FR-negative A549 cells was not apparently increased at the same experimental conditions. Cytotoxicity assay showed 60% and 58% decrease in IC₅₀ values for HeLa and KB cells, while only a slight decrease for A549 cells, following treatment with folate modified formulations. The enhanced intracellular delivery of FA modified micelles in MCF-7/ADR cells was also observed. In vivo antitumor tests revealed DOX entrapped FA-PEOz-PCL micelles effectively inhibited the tumor growth and reduced the toxicity to mice compared with free DOX. The current study showed that the targeted nano-vector improved cytotoxicity of DOX and suggested that this novel PEOz endowed stealthy micelle system held great promise in tumor targeted therapy.     

Poly (ethylene glycol) prodrug for anthracyclines via N-Mannich base linker: Design, synthesis and biological evaluation

Poly (ethylene glycol)s (PEGs) are potential drug carriers for improving the therapeutic index of anticancer agents. In this work, a novel methodology for constructing PEG prodrug of anthracycline anticancer drugs was developed based on N-Mannich base of salicylamide and its 2-acyloxymethylated derivative. The resultant conjugates first subjected to in vitro hydrolysis testing, which revealed the release behavior of newly synthesized PEG prodrugs could be adjusted by the status of 2-hydroxy group of salicylamide. These PEG prodrugs also demonstrated superior cytotoxicity in antiproliferative assay. O-blocked doxorubicin prodrug with PEG20k as carrier was selected for further in vivo assessments and presented longer circulating life in pharmacokinetic experiment. This high molecular prodrug was also found to be more efficacious against S-180 xenografted tumor than equivalent amount of doxorubicin.     

Integrated combination delivery of IDO inhibitor and paclitaxel for cancer treatment

In order to realize the combination of chemotherapy and immunotherapy, a reduction-responsive paclitaxel (PTX) prodrug PEG-SS-PTX was synthesized and used as a carrier to encapsulate IDO inhibitor CY-1-4 for preparing PEG-SS-PTX/CY-1-4 NPs. PEG-SS-PTX/CY-1-4 NPs were evaluated by cytotoxicity, immunogenic cell death (ICD) induction ability and anti-tumor efficacy. Dynamic light scattering (DLS) results showed that the size of PEG-SS-PTX/CY-1-4 NPs was about 149 nm. In vitro experiments indicated that its cytotoxicity was in a concentration-dependent manner, and it induced the ICD of B16-F10 cells. In vivo studies in melanoma mouse model indicated that PEG-SS-PTX/CY-1-4 NPs significantly inhibited the tumor growth and reduced the expression of IDO in tumor tissues. Moreover, it increased the rate of CD8⁺ T cells in the spleen. In summary, PEG-SS-PTX/CY-1-4 NPs achieved good anti-tumor effects and reduced the dose of chemotherapy drugs, which was a safe and effective combined delivery system.     

抗肿瘤前药在肿瘤靶向治疗中的新进展

化疗是临床上治疗肿瘤的主要途径之一,但化疗药物在肿瘤部位的低浓度及系统毒性仍是其临床应用受限的首要问题。前体药物通过对原药的化学结构或药物剂型给予一定修饰,大大克服了化疗药物的缺点,开辟了一条靶向治疗肿瘤的新途径。目前,新发展的抗肿瘤前药有导向酶活化前药、载体前药、脂质前药等,现对其研究进展和应用做一综述。     

靶向肿瘤微环境的紫杉醇前药研究进展

紫杉醇前药（paclitaxel prodrugs）的设计是一种提高药物制剂成药性、降低其毒副作用、增强抗肿瘤效果的有效手段。随着对前药研究的深入,利用肿瘤过表达的受体、酶、转运蛋白、谷胱甘肽及活性氧自由基以及肿瘤组织弱酸性及低氧环境等作为靶标进行的紫杉醇靶向性前药的研究已取得极大进展。综述近年来以肿瘤微环境特殊的病理与生理特征为靶标的紫杉醇前药的研究进展。     

Preparation and characterization of water-soluble prodrug, liposomes and micelles of Paclitaxel

Alternative formulations of paclitaxel were developed in order to improve its aqueous solubility, and characterized in vitro. A methacrylic acid based nanoconjugate of paclitaxel was synthesized by a simple esterification reaction with molecular weight of 1657 Da. The in vitro hydrolysis study on the prodrug of paclitaxel in presence of rat plasma has shown that the ester bond was quite stable (less than 1% of paclitaxel was liberated from prodrug in 24 h). This water-soluble prodrug was encapsulated into polyethylene glycol coated liposomes optimized with saturated lipids, to overcome the physical instability associated with paclitaxel. Under in vitro testing, prodrug liposomes seem very impressive with release of only 45% of payload in 180 h. Further, chemical as well as physical stability studies have shown that liposomes were stable without any signs of crystallization of paclitaxel. In addition, paclitaxel was covalently coupled to poloxamer via methacrylic acid linker to obtain a micelle forming conjugate. Evidence for self-assembly of this conjugate into micelles was provided by fluorescence spectroscopy, light scattering and differential scanning calorimetry techniques. Micellization of the conjugate was thermodynamically favored and the core of resulting micelles exhibited higher microviscosities (than poloxamer micelles). Release studies using dialysis technique along with high performance liquid chromatography revealed that paclitaxel is liberated from micelle in the form of methacrylic acid oligomer based prodrug in a gradual manner. These preliminary studies provided indication on the performance and feasibility of testing these carrier systems as a safer alternative to the Cremophor EL based paclitaxel formulation.     

Enhanced oral bioavailability of paclitaxel in pluronic/LHR mixed polymeric micelles: preparation, in vitro and in vivo evaluation

In order to enhance paclitaxel oral bioavailability, mixed polymeric micelles that comprised of pluronic copolymers and low molecular weight heparin-all-trans-retinoid acid (LHR) conjugate were developed. PTX-loaded mixed polymeric micelles (MPMs) were prepared by dialysis method with high drug loading 26.92 ± 2.08% and 25.82 ± 1.9% for F127/LHR and P188/LHR MPMs respectively, and were found to be spherical in shape with an average size of around 140 nm and a narrow size distribution. In vitro release study showed that pluronic/LHR MPMs exhibited delayed release characteristics compared to Taxol and faster drug release profile compared to LHR plain polymeric micelles (PPMs). The cytotoxic activity of PTX-loaded pluronic/LHR MPMs was slightly higher than LHR PPMs in MCF-7 cells (p<0.01). In situ effective permeability of PTX through rat small intestine was 5- to 6-fold higher with mixed micelles than that of Taxol. Moreover, pluronic/LHR MPMs achieved significantly higher AUC and C(max) level than both of LHR PPMs and Taxol. This enhancement might be due to the inhibition of both P-glycoprotein efflux system and cytochrome P450 metabolism by pluronic copolymers. The current results encourage further development of paclitaxel mixed polymeric micelles as an oral drug delivery system.     

Remote loading paclitaxel–doxorubicin prodrug into liposomes for cancer combination therapy

The combination of paclitaxel (PTX) and doxorubicin (DOX) has been widely used in the clinic. However, it remains unsatisfied due to the generation of severe toxicity. Previously, we have successfully synthesized a prodrug PTX-S-DOX (PSD). The prodrug displayed comparable in vitro cytotoxicity compared with the mixture of free PTX and DOX. Thus, we speculated that it could be promising to improve the anti-cancer effect and reduce adverse effects by improving the pharmacokinetics behavior of PSD and enhancing tumor accumulation. Due to the fact that copper ions (Cu²⁺) could coordinate with the anthracene nucleus of DOX, we speculate that the prodrug PSD could be actively loaded into liposomes by Cu²⁺ gradient. Hence, we designed a remote loading liposomal formulation of PSD (PSD LPs) for combination chemotherapy. The prepared PSD LPs displayed extended blood circulation, improved tumor accumulation, and more significant anti-tumor efficacy compared with PSD NPs. Furthermore, PSD LPs exhibited reduced cardiotoxicity and kidney damage compared with the physical mixture of Taxol and Doxil, indicating better safety. Therefore, this novel nano-platform provides a strategy to deliver doxorubicin with other poorly soluble antineoplastic drugs for combination therapy with high efficacy and low toxicity.