聚乳酸乙醇酸的生物降解和安全性研究进展

聚乳酸乙醇酸(PLGA)的降解主要是通过酯键水解,自催化作用和巨噬细胞吞噬;水解产物为乳酸和乙醇酸,均可代谢分解生成二氧化碳和水,分别通过肺和肾排出体外,仅有微量的原型聚合物经尿液排出,体内没有蓄积现象.PLGA具有良好的生物相容性和可生物降解性,作为组织工程支架和药物控释系统材料是安全的.美国食品药品管理局(FDA)已经批准将PLGA作为组织工程细胞支架和药物载体,在美国、日本市场应用多年,未见严重的不良反应报道.目前国产PLGA的质量和控释微球药品的开发研究仍需要提高,尤其是制剂的载药量、控释技术以及稳定性技术.介绍PLGA的生物降解与安全性研究进展,为开发PLGA控释系统提供参考.     

聚乳酸、聚乳酸乙醇酸共聚物微球的制备及体外释放影响因素研究进展

目的:对近年来以PLA、PLGA为载体的微球剂的研究进展进行综述。方法:查阅近10年来有关PLA、PLGA微球研究的国内外文献,介绍此类微球的制备方法和影响其体外释放等性质的主要因素。结果:PLA、PLGA的性质、药物的性质及微球的制备工艺等对微球的体外释放等性质均有重要的影响。结论:对以PLA、PLGA为载体制备的药物微球,有待于更进一步的研究和开发     

影响聚酯微球中药物释放的因素

聚酯材料因其原料易得、容易加工、生物相容性好、具有可生物降解性等优点,已经成为当今药物载体材料中的一大研究热点。现综合国内外的有关报道对可生物降解聚酯材料作为药物载体制备微球制剂的研究进展进行了综述。针对目前限制聚酯材料微球制剂临床应用存在的问题,从聚合物、药物、制备工艺、附加剂、辐射灭菌5个方面对影响聚乳酸(PLA)和聚乳酸乙醇酸共聚物(PLGA)缓释微球中药物释放的因素进行了重点介绍,为研究聚酯微球中药物的释放提供思路。     

聚乳酸、聚乳酸乙醇酸共聚物微球的制备及体外释放影响因素研究进展

目的：对近年来以PLA，PLGA为载体的微球剂的研究进展进行综述。方法：查阅近10年来有关PLA，PLGA微球研究的国内外文献，介绍此类微球的制备方法和影响其体外释放等性质的主要因素。结果：PLA，PLGA的性质，药和折性质及微球的制备工艺等对微球的体外释放等性质均有重要的影响。结论：对以PLA，PLGA为载体制备的药物微球，有待于更进一步的研究和开发。     

可生物降解的聚乳酸-羟基乙酸共聚微球制备与性能研究进展

生物可降解材料乳酸-羟基乙酸共聚物(PLGA)有良好的生物相容性和安全性,在体内降解为二氧化碳和水.由于PLGA易于合成、质量稳定,具有生物兼容性、生物可降解性、机械强度、降解速度可调节性和良好的可塑性,自2000年后被大量用作微球控释系统的载体材料.     

乳酸-羟基乙酸共聚物微球、纳米粒载药体系的研究进展

目的:扩大乳酸-羟基乙酸共聚物微球、纳米粒载药体系的适用范围,并为其他缓控释剂型研发提供参考。方法:查阅文献,综述乳酸-羟基乙酸共聚物(PLGA)微球、纳米粒的表面修饰,PLGA与其他聚合物聚合作为药物载体改变释药行为,PLGA与其他聚合物制备双层微球及修饰特异标记用于疾病诊断的研究进展。结果与结论:PLGA微球、纳米粒经过适当的修饰,可以扩大其应用范围,更好地用作药物特别是基因、疫苗及抗原等某些特殊药物的载体,但有待进一步临床研究考察。     

抗生素缓控释给药系统——载药微球的研究与开发

利用具良好生物相容性和生物可降解性的聚合物制得的微球作为一种新型药物载体,具有良好的缓控释作用,并具有一定的靶向性,可用于口服和注射,在药学领域和临床上有着广阔的应用前景。综述近年来各种抗生素缓控释微球制剂的研究与开发。     

聚乳酸／乳酸／-乙醇酸共聚物微球制剂研究的新进展

简要介绍了PLA／PLGA及其制剂的原理，并叙述近年来国内PLA／PLGA在新型微球基材、蛋白质和多肽类药物微球、疫苗佐剂类微球和化学合成药物微球的进展情况。     

PLGA包埋硫酸庆大霉素缓释微球的制备及体外释放行为

以生物可降解乙交酯和丙交酯的无规共聚物(PLGA)为载体,将硫酸庆大霉素分散在PLGA的有机溶液中,采用复乳溶剂挥发法制备了药物缓释微球。研究搅拌速度、PLGA浓度、乳化剂浓度和硫酸庆大霉素溶液体积对微球粒径的影响,观察微球的表面形貌,测定微球粒径、粒径分布和包封率,评价载药微球的体外释放行为。结果表明,采用甲基纤维素为乳化剂制备的微球形态完整,中粒径为(130±30)μm,微球中硫酸庆大霉素的包封率均在36%以上,平均42%,最高达56%。硫酸庆大霉素/PLGA微球具有显著的药物缓释作用,体外释放30d的累积释药率达80%以上。     

聚乳酸-羟基乙酸载药微球控制体外释放因素的研究进展

体外释放行为研究是为了能够更好地反映微球在体内的释药状况,有利于筛选出更理想的处方及工艺.体外释放度试验是微球制剂释药速度的体外评价方法,可以了解制剂的生物药剂学特点和预测药物在体内的释放和吸收,使体外释放获得的数据能与体内数据具有相关性.体外释放度实验是常用的微球制剂体外释药速度的评价方法.建立体内外相关性后就能以体外实验代替体内实验来测定生物利用度和生物等效性.根据药物的性质、给药途径和释药时间,选用不同的聚乳酸-羟基乙酸(PLGA)采用相应的制备工艺;通过调整PLGA的组成、分子量、载药量及粒径的大小等因素,能控制药物达到不同的释放速度或程度.     

Single and Coencapsulation of lnterferon-γ in Biodegradable PLA Microspheres for Optimization of Multicomponent Vaccine Delivery Vehicles

Interferon-γ (IFN-γ) is a cytokine with potential for application in immunotherapy. Because of side effects following systemic administration, the use of such cytokines has been limited. The encapsulation of such agents in biodegradable microspheres is desirable, facilitating controlled release of drug from targetable devices. The combination of cytokines with antigens in a microsphere system may be of practicable value in providing a safe and novel class of carrier. Low-molecular-weight poly (L-lactide) (PLLA) was used for microsphere production by both single- and double-emulsion solvent evaporation techniques. The small microspheres produced in this study have the potential for mucosal delivery, desirable for vaccine delivery systems, being in the region of 1 μm in diameter with smooth spherical surfaces. The effect of inclusion of diluent proteins on the encapsulation efficiency and release characteristics of both types of preparations is discussed together with the mechanisms of release. The coencapsulation of IFN-γ with other proteins in such formulations requires investigation of the effect of each ingredient on the subsequent particle formation and release characteristics.     

Drug delivery into the brain using poly(lactide-co-glycolide) microspheres

Among the strategies developed for drug delivery into the CNS, locally controlled drug release by the way of an implantable polymeric device has been developed in recent years. The first polymeric devices developed were macroscopic implants needing open surgery for implantation. Over the last few years, poly(lactide-co-glycolide) microspheres have been shown to be safe and promising for drug delivery into the brain. Poly(lactide-co-glycolide) is biodegradable and biocompatible with brain tissue. Due to their size, these microspheres can be easily implanted by stereotaxy in discrete, precise and functional areas of the brain without causing damage to the surrounding -tissue. Brain tumour treatments have been developed using this approach and clinical trials have been performed. Potential applications in neurodegenerative diseases have also been explored, particularly neurotrophic factor delivery and cell therapy.     

Drug delivery into the brain using poly(lactide-co-glycolide) microspheres

Among the strategies developed for drug delivery into the CNS, locally controlled drug release by the way of an implantable polymeric device has been developed in recent years. The first polymeric devices developed were macroscopic implants needing open surgery for implantation. Over the last few years, poly(lactide-co-glycolide) microspheres have been shown to be safe and promising for drug delivery into the brain. Poly(lactide-co-glycolide) is biodegradable and biocompatible with brain tissue. Due to their size, these microspheres can be easily implanted by stereotaxy in discrete, precise and functional areas of the brain without causing damage to the surrounding -tissue. Brain tumour treatments have been developed using this approach and clinical trials have been performed. Potential applications in neurodegenerative diseases have also been explored, particularly neurotrophic factor delivery and cell therapy.     

胶原微球作为药物载体的研究进展

近年来,微粒给药系统的发展为大分子药物靶向及缓控释给药提供更多的方法,但对药物载体的要求也越来越高。胶原因其良好的生物相容性、生物可降解性及极低的免疫原性成为药物载体材料研究的新热点。本文对胶原作为药物载体的研究进展进行了综述,包括胶原微球、胶原包衣微球及胶原复合材料微球的研究。     

Recent advances in the use of microspheres for targeted therapy

In recent years the concept of using small colloidal particles for the selective delivery of drugs has been explored experimentally using a variety of different physical systems (for example, phospholipid vesicles (liposomes), triglyceride emulsions, albumin microspheres) and routes of administration. In such studies the aim has been to target a potent pharmacological agent on an organ or tissue site, thereby reducing adverse reactions and side-effects, or to provide a means of controlled release. The design of appropriate delivery systems must take into account the nature of the target and physiological barriers to targeting as well as factors such as drug loading and drug release, stability of the carrier system and its biocompatibility and biodegradation. Targeting with microspheres can be divided into passive methods that rely upon physiological and physicochemical determinants such as entrapment in capillary beds (lungs - particle size) or uptake by phagocytic cells (liver-surface characteristics), an active method whereby the particle is directed to a specific site through the use of surface coatings (surfactants, glycolipids, monoclonal antibodies) or a material sensitive to an external influence. Candidate systems presently under study are described. These include lipid emulsions for intravenous administration and microspheres for intra-articular delivery.     

PLGA微球控释系统的突释及其控制

针对目前限制PLGA微球控释系统临床应用的突释问题，重点介绍了近年来国内外有关的研究进展，包括突释现象、突释原因、影响因素和控制突释的方法和技术。     

PLGA微球的修饰及其应用

微球作为新型的药物载体系统已广泛用于临床研究,高分子化合物材料聚乳酸-羟基乙酸(pdy lactic-co-glycolic acid,PLGA)因其良好的生物相容性和生物可降解性备受关注。近年来,PLGA微球的研究一直是热门,针对其释放缺陷出现了很多复合修饰方法,主要包括环糊精、壳聚糖、聚乳酸、明胶、泊洛沙姆、聚乙烯亚胺等高分子材料的联用、针对末端基团进行化学修饰以及制备成核壳型微球,在保证包封率的情况下大大降低突释,改善药物释放曲线,从而在药物传递、基因治疗、影像诊断、组织工程等领域得到了广泛的应用。     

国外上市新型注射剂的研究进展

纳米粒、微球、脂质体、原位凝胶和微乳或亚微乳等给药系统能减少药物在体内外的降解,实现药物的控制释放.基于上述给药系统的新型注射剂已成为药物研发的关注热点.本文综述了近年国外上市的新型注射剂的剂型特点及其临床应用概况,并介绍了几种新型注射装置.     

Sustained-release ophthalmic drug delivery systems for treatment of macular disorders: present and future applications

Macular disease currently poses the greatest threat to vision in aging populations. Historically, most of this pathology could only be dealt with surgically, and then only after much damage to the macula had already occurred. Current pathophysiological insights into macular diseases have allowed the development of effective new pharmacotherapies. The field of drug delivery systems has advanced over the last several years with emphasis placed on controlled release of drug to specific areas of the eye. Its unique location and tendency toward chronic disease make the macula an important and attractive target for drug delivery systems, especially sustained-release systems. This review evaluates the current literature on the research and development of sustained-release posterior segment drug delivery systems that are primarily intended for macular disease with an emphasis on age-related macular degeneration.Current effective therapies include corticosteroids and anti-vascular endothelial growth factor compounds. Recent successes have been reported using anti-angiogenic drugs for therapy of age-related macular degeneration. This review also includes information on implantable devices (biodegradable and non-biodegradable), the use of injected particles (microspheres and liposomes) and future enhanced drug delivery systems, such as ultrasound drug delivery. The devices reviewed show significant drug release over a period of days or weeks. However, macular disorders are chronic diseases requiring years of treatment. Currently, there is no 'gold standard' for therapy and/or drug delivery. Future studies will focus on improving the efficiency and effectiveness of drug delivery to the posterior chamber. If successful, therapeutic modalities will significantly delay loss of vision and improve the quality of life for patients with chronic macular disorders.