酸敏释药胶束肿瘤靶向给药系统的研究进展

酸敏释药胶束作为一种新型的靶向给药系统,具有增溶疏水性药物、载药量高,酸敏感释药等优势。可通过物理包埋或酸敏感键共价连接药物的方式包载药物。在肿瘤组织的偏酸环境下,物理包埋载药胶束由于共聚物亲脂嵌段质子化或亲水亲脂嵌段水解分离、共聚物失去两亲性,胶束解聚释药;而以共价连接方式包载的药物经酸敏键断裂释放。现主要从载药方式及释药机制方面探讨酸敏释药胶束作为肿瘤靶向给药系统的研究进展。     

普罗布考胶束给药系统的制备及口服淋巴吸收评价

目的研究一种可促进普罗布考口服淋巴吸收的胶束给药系统。方法使用甲氧基聚乙二醇磷脂酰乙醇胺(mPEG-DSPE)作为载体材料,制备载普罗布考胶束给药系统并进行优化,并通过清醒大鼠淋巴插管模型评价其提高药物口服淋巴转运的作用。结果经处方优化以后,以mPF~DSPE作为载体材料制备的载普罗布考胶束的包封率>90%。清醒大鼠淋巴插管模型考察结果表明,载药胶束8 h内的淋巴转运药物累积量约为混悬组的3倍。结论 mPEC-DSPE胶束给药系统可显著提高普罗布考的淋巴转运量。     

聚合物胶束在提高抗肿瘤疗效中的研究进展

恶性肿瘤是严重威胁人类健康的一类疾病。功能化的聚合物胶束作为一种新型的纳米给药系统在口服、静脉注射给药治疗肿瘤中发挥着重要的作用。本文从口服给药以及静脉给药两个方向分别探讨了生物黏附胶束,主动靶向胶束,pH敏感胶束,温度敏感胶束以及逆转多药耐药胶束在提高抗肿瘤疗效中的重要作用以及最新研究进展。     

聚合物胶束作为药物载体及其在肿瘤靶向方面的研究进展

聚合物胶束具有粒径小、稳定性高、滞留时间长、良好的生物相容性等特点,这些优良性质使得聚合物胶束作为药物载体具有许多独特的优势。近年来,涌现了许多围绕聚合物胶束设计肿瘤靶向给药系统的报道,包括利用肿瘤的病理学性质,设计被动靶向给药系统和对聚合物胶束进行表面修饰,设计主动靶向给药系统。本文主要综述了聚合物胶束作为肿瘤靶向药物载体的研究进展。     

壳聚糖衍生物胶束的功能化修饰及其在不同给药系统中的应用进展

目的:综述壳聚糖(CS)衍生物胶束功能化修饰及其在不同给药系统中的应用进展,以期为其深入研究和应用提供参考。方法:以"壳聚糖""胶束""给药系统""Chitosan""Micelle""Drug delivery system"等为关键词,组合查询1995年1月-2019年5月在中国知网、万方数据、Web of Science等数据库中发表的相关文献,对其各衍生物胶束的功能化修饰及其在不同给药系统中的应用进行综述。结果与结论:共检索到相关文献478篇,其中有效文献37篇。CS作为一种性能优良、可修饰性强、生物相容性高的天然高分子材料,可通过疏水骨架、长循环、P-糖蛋白抑制、靶向、刺激信号响应等多种功能化修饰装载疏水性药物,制成CS衍生物胶束,在黏膜给药、眼部给药、口服给药等多种给药系统中均展现出巨大的应用潜力。目前,CS衍生物胶束在解决难溶性药物溶解度、促进药物渗透、增强靶向、提高生物利用度等方面已取得长足发展,但多停留在体外研究,且对详细作用机制的研究较少。若要将其成功应用于临床,尚需对CS衍生物胶束的体内稳定性、药物释放度、药物靶向效率等关键问题进行深入考察。     

聚合物胶束在经皮给药系统中的应用

摘 要 目的：综述聚合物胶束作为药物载体在经皮传递系统中的应用进展。方法: 根据国内外发表的最新文献,对聚合物胶束的制备方法、促进皮肤渗透的机制、释药过程及其在经皮给药系统中的应用进行分析与讨论。结果: 聚合物胶束具有增加难溶性药物的溶解度,促进药物的经皮吸收等作用,作为药物载体在经皮传递系统的应用越来越广泛。结论:聚合物胶束可作为药物载体被广泛用于经皮给药系统的研究中,具有较好的发展前景。     

纳米给药系统在难溶性药物制剂研究中的应用

近年来,难溶性药物给药系统一直是制剂学研究的重点和难点之一。纳米载体由于其良好的生物相容性及可装载大量难溶性药物等特点而被广泛应用于难溶性药物给药系统的研究,该类载体主要包括纳米粒、脂质体、纳米乳、聚合物胶束、纳米混悬剂等。本文结合近几年国内外文献报道,对纳米给药系统在难溶性药物制剂研究中的最新进展进行概述。     

聚乙二醇修饰脂质小分子在胶束给药系统中的研究进展

脂质分子因具有无毒性,无免疫源性以及良好的生物兼容性,广泛应用于药物载体研究中。经聚乙二醇修饰的脂质具有双亲性,在水中可自组装形成胶束。该类聚合物载体能够增强药物的溶解度及稳定性,改善药物在体内的药动学行为,增强疗效等,在纳米给药系统中具有广阔的应用前景。本文综述了在胶束给药系统中应用较多的聚乙二醇化脂质小分子,主要包括聚乙二醇修饰的磷脂,胆固醇,脂肪酸等。     

聚合物胶束作为肿瘤靶向给药载体的研究

聚合物胶束是近年来出现的一种新型胶态药物载体,具有很多优良的性能,如体内外稳定性高、良好的生物相容性、难溶性药物的增溶作用等.它可以作为靶向肿瘤的给药载体,通过多种机制,如环境响应的聚合物胶束、特异性配基耦合的聚合物胶束、免疫聚合物胶束、通透性增强与滞留(EPR)效应、肿瘤的血管系统等途径来实现药物靶向给药.现主要讨论肿瘤给药的靶向策略和聚合物胶束作为靶向肿瘤给药载体的研究进展.     

pH响应性聚合物胶束及其在抗癌药物给药系统中的研究进展

 聚合物纳米粒作为一种有效的药物运送载体已经受到广泛的关注,具有环境响应性的聚合物胶束的制备及应用是目前引人瞩目的研究方向。最近,pH响应性聚合物胶束已被用作抗癌药物的运送载体,其显著的优势就是能够靶向给药于病灶部位,从而降低不良反应,提高抗癌药物的化疗指数。文中综述了pH值响应性的聚合物胶束的两种主要制备策略,即依赖于共聚物骨架中的“可滴定”基团;引入可被酸降解的连接臂,还介绍了pH值响应性聚合物胶束在抗癌药物给药系统中的应用。     

Reverse micelle-based microencapsulation of oxytetracycline hydrochloride into poly-d,l-lactide-co-glycolide microspheres

The objectives of this study were to solubilize oxytetracycline hydrochloride (HCl) in reverse micelles to prepare poly-d,l-lactide-co-glycolide (PLGA) microspheres and to explore parameters affecting its encapsulation efficiency. Oxytetracycline HCl was dissolved in the reverse micelles consisting of cetyltrimethylammonium bromide, water, and ethyl formate. A PLGA polymer was then dissolved in the reverse micellar solution, and a modified solvent quenching procedure was carried out to prepare PLGA microspheres. Encapsulation efficiencies of oxytetracycline HCl ranged from 2.3 ± 0.2 to 24.9 ± 4.6%, depending on experimental conditions. Important parameters affecting its encapsulation efficiency included the amounts of water used to prepare the reverse micelles and PLGA polymer. With regard to microsphere morphology, the reverse micellar process produced the microspheres with smooth and pore-free surfaces. In particular, their internal matrices did not possess hollow cavities that were frequently observed when a typical double emulsion technique was used to make microspheres. In summary, it was possible to encapsulate oxytetracycline HCl into PLGA microspheres via the ethyl formate-based reverse micellar technique. We also anticipate that the use of ethyl formate could avoid environmental and human toxicity issues associated with methylene chloride.     

Structural and ligand-binding properties of serum albumin species interacting with a biomembrane interface

In the process of drug development, preclinical testing using experimental animals is an important aspect, for verification of the efficacy and safety of a drug. Serum albumin is a major binding protein for endogenous and exogenous ligands and regulates their distribution in various tissues. In this study, the structural and drug-binding properties of albumins on a biomembrane surface were investigated using reverse micelles as a model membrane. In reverse micelles, the secondary structures of all albumins were found, to varying degrees, to be intermediate between the native and denatured states. The tertiary structures of human and bovine albumin were similar to those of the native and intermediate states, respectively, whereas those of the dog, rabbit, and rat were in a denatured state. Thus, bovine albumin is an appropriate model for studying structural changes in human albumin in a membrane-water phase. Binding studies also showed the presence of species difference in the change in binding capacity of albumins during their interaction with reverse micelles. Among the albumins, rat albumin appears to be a good model for the protein-mediated drug uptake of human albumin in a biomembrane environment. These findings are significant in terms of the appropriate extrapolation of pharmacokinetics and pharmacodynamics data in various animals to humans.     

Design, optimization and in vitro evaluation of reverse micelle-loaded lipid nanocarriers containing erlotinib hydrochloride

Erlotinib hydrochloride (ERLO) belongs to the tyrosine kinase inhibitor family and is used for the treatment of pancreatic cancers. In the present study, ERLO was entrapped in lipid nanocarriers by means of reverse micellar incorporation. This study aims to optimize the formulation of ERLO-loaded nanoparticles. Surfactants forming reverse micelles in Labrafac(?) were filled with ERLO under various conditions. Both the initial amount of drug incubated with reverse micelles and the surfactant composing the reverse micelles are crucial parameters for reverse micelle capacity to load ERLO. The optimal loading system for reverse micelles was obtained with a mix of sorbitan trioleate (Span(?) 85) and Labrafac(?) oil at a 1:1 (w/w) ratio. Reverse micelle composition influenced the nanocarrier's hydrodynamic diameter, polydispersity index, and zeta potential. In lipid nanoparticles formulated by using the phase inversion temperature (PIT) method, ERLO entrapment efficiency was around 56%. In vitro, the efficacy of ERLO-loaded nanocarriers on BxPC-3 pancreatic adenocarcinoma cells was comparable to free ERLO, and led to a cell death rate of around 40%.     

Anticancer drug delivery of PEG based micelles with small lipophilic moieties

Herein, we reported a new type of self-assembly micelles based on amphiphilic polymers of cinnamate and coumarin derivatives modified PEG for drug delivery applications. Lipophilic cinnamic acid (CIN) and 7-carboxyl methoxycoumarin (COU) were immobilized on the terminal groups of poly(ethylene glycol) (PEG) to prepare amphiphiles. The amphiphiles self-assembled into micelles. The amphiphiles and micelles were characterized by ¹H NMR, FT-IR, DLS and TEM. Doxorubicin (DOX) was used as a model drug to investigate the lipophilic moieties effects on the drug release behaviors. The DOX loaded micelles were incubated with HepG2 liver cancer cells to study the in vitro anticancer activities. The results showed that DOX could be encapsulated in the micelles efficiently. The mean diameter of the drug loaded micelles was around 100 nm. Drug release profile revealed that the release rate of DOX loaded COU-PEG-COU micelles was significantly slower than that of CIN-PEG-CIN micelles. The DOX loaded micelles could be internalized in HepG2 cells. Both CLSM and flow cytometry results showed that the DOX loaded CIN-PEG-CIN micelles exhibited better anticancer efficacy.     

Enhanced cytotoxicity of core modified chitosan based polymeric micelles for doxorubicin delivery

In this study, the cytotoxicity of doxorubicin (DOX) loaded stearic acid grafted chitosan oligosaccharide (CSO-SA) micelles and its core modified drug delivery systems were investigated in vitro. The in vitro drug release experiments using cellular culture medium, Roswell Park Memorial Institute 1640 (RPMI-1640) medium as a dissolution medium confirmed that the DOX release from CSO-SA micelles was successfully delayed by the core modification of CSO-SA micelles with stearic acid (SA). The cell viability assay against A549 cells indicated the 50% inhibition concentration (IC(50)) of blank CSO-SA micelles and the core modified CSO-SA micelles was 369 +/- 27 microg/mL and 234 +/- 9 microg/mL, respectively. The entrapment of DOX by CSO-SA micelles could decrease the IC(50) of DOX from 3.5 to 1.9 microg/mL, and a further reduction to 0.7 microg/mL could result by the core modification of CSO-SA micelles. The fluorescence image observations of DOX and DOX concentration measurements inside A549 cells demonstrated that the DOX concentration inside cells was increased by the entrapment of CSO-SA micelles, and further enhanced by the core modification of CSO-SA micelles. The results indicated that the CSO-SA micelles with modified cores could be useful as a drug delivery vehicle for cancer chemotherapy.     

Solubilization of timolol maleate in reversed micellar systems. Measurement of particle size using SAXS and PCS

Small angle X-ray scattering (SAXS) and photon correlation spectroscopy (PCS) are two methods to measure particle sizes in the order of 10 nm magnitude, which can be used to characterize reversed micellar systems, in this case reverse micelles consisting of lecithin and isopropyl myristate (IPM). In this study these micelles are loaded with different concentrations of the amphiphilic anti-glaucoma drug timolol maleate (TM). The PCS results are consistent with those yielded by SAXS, showing a decrease of particle size with higher TM concentration. In addition, SAXS is capable to give information about the particle shape. This kind of evaluation yields an ellipsoidal shape for micelles with low drug loads, which transform into nearly spherical micelles at higher drug concentrations.     

Photodynamic effect in lysozyme: a kinetic study in different micellar media

Abstract: The influence of medium heterogeneity on the kinetics of the photodynamic effect on native protein lysozyme (Lyso), as well as the interaction of protein and the medium, anionic (SDS) micelles, neutral (Triton X‐100) micelles and reversed micelles of AOT, were investigated at pH 8. The interaction between Lyso, Triton X‐100 and SDS micelles was quantified by determining the respective associations constant (K_Lyso). Values were 37 m ^–1 for Triton X‐100 and 514 m ^–1 for SDS, indicating that the Lyso molecule binds Triton X‐100 micelles effectively and SDS micelles even more strongly. Time‐resolved phosphorescence detection (TRPD) indicates that the protein interacts with O₂ (¹Δ_g), with overall rate constants of the order of 10⁸ m ^–1/s in direct micelles and 10⁷ m ^–1/s in reverse micelles. Apparent reactive rate constants for eosin‐sensitized photo‐oxidation (singlet molecular oxygen [O₂ (¹Δ_g)]‐mediated) of the protein were determined through oxygen uptake experiments for the direct micelles, while the fade in the protein fluorescence spectrum upon sensitized irradiation was used in AOT. The results indicate that the O₂ (¹Δ_g) attack on the interior of Lyso on amino acid residues, was more effective in leading to a photo‐oxidative reaction in SDS and in Triton X‐100 at surfactant concentrations < 1 × 10^–2 M than in a homogeneous solution. However, Lyso reactivity reached a maximum when the concentration of micelles was ≈ 1 × 10^–5, the same as the protein concentration In AOT reverse micelles, the quenching rate constants decreased > 75% with respect to water. This effect can be attributed to the decrease in accessibility of the amino acid residues to O₂ (¹Δ_g).     

胶束传递系统逆转肿瘤多药耐药的研究进展

肿瘤多药耐药是目前肿瘤治疗的一大障碍。研究采用药物传递系统如胶束、脂质体、纳米粒等, 以逆转多药耐药, 显示其安全可靠, 并具有良好的应用前景。本文重点综述了药物传递系统中的聚合物胶束逆转多药耐药的研究结果及其可能的作用机制。随着研究的深入, 药物传递系统在逆转肿瘤多药耐药的研究领域将发挥更加重要的作用。     

Preparation, pharmacokinetics and tissue distribution of micelles made of reverse thermo-responsive polymers

New reverse thermo-responsive polymers, poly(ethylene oxide)–poly(propylene oxide) multiblock copolymers (poly(ether-carbonate)s) were synthesized. The micelles made of new reverse thermo-responsive polymers were also prepared loaded with the poorly soluble anticancer drug, hydroxycamptothecin (HCPT). The structure characterization of poly(ether-carbonate)s was determined by ¹H NMR and FT-IR analysis. The critical micelle concentration (CMC), critical micelle temperature (CMT), size distribution and drug release in vitro were determined. The pharmacokinetics and tissue distribution in vivo for novel copolymer micelles were studied. The experimental results showed that the micelles was spherical in appearance and dispersed well. The process of HCPT release from micelles in vitro was composed of two steps, abrupt release and sustained release. After i.v. administration (2 h), the drug concentration of poly(ether-carbonate) micelles group in liver in mice was 3.46 μg/g, while that of HCPT injection group was 0.401 μg/g. Compared with HCPT injection, the elimination half-life of poly(ether-carbonate) micelles group was prolonged remarkably from 1.3 to 12.5 h. The poly(ether-carbonate) micelles showed a combination of liver targeting and sustained drug release in experiments on animals.