聚己内酯微粒的生物降解行为

由于微包囊药物制剂具有降低药物毒副作用、防止药物失活、减少服药次数以及靶向给药的效果,从而既可提高病灶部位的药物浓度,又可减小对机体其它部位的损伤,因此成为较理想的药物释放体系,以至目前在药物释放体系中,微包囊药物释放体系得到了广泛的应用．生物降解性高分子是理想的药物包裹材料,由于它在药物释放完毕后可以在体内降解、而后被机体代谢或吸收,不需再手术取出,因此,用高分子微包囊药物释放体系治疗癌症等疑难病症正在成为国际上共同的研究热点［１］．聚己内酯（ＰＣＬ）是兼具良好力学性能和药物通透性能的生物降解…     

生物降解性聚己内酯-聚醚嵌段共聚物的合成及表征

生物降解性高分子具有在生理条件下可以自行降解、代谢,使之被机体吸收或被排泄的特点,因此可以免除在进入体内后需再经手术方法取出的麻烦。由此,生物降解性高分子在作为药物释放体系的药物载体和在医疗上作为外科手术组织修饰材料等方面具有十分广阔的应用前景,并且成为当前生物医用高分子领域的一个重要的研究课题。     

葡萄糖敏感苯硼酸基高分子纳米药物传输体系

近年来,智能葡萄糖敏感自调式药物传递系统备受关注。这种智能药物释放系统能够模拟胰腺分泌胰岛素的生理模式而精准调控药物释放并控制血糖水平,在糖尿病治疗中具有良好的应用前景。其中,苯硼酸(PBA)功能化的葡萄糖敏感高分子纳米载体成为近年来的研究热点之一。该类材料具有体系稳定、可长期储存、可逆的葡萄糖敏感性能等优势。根据响应因素不同,葡萄糖敏感药物传递系统可分为pH响应、温度响应和光响应等类型。本文重点介绍了基于PBA的葡萄糖敏感高分子纳米药物载体的发展过程、性能和应用,并对该领域的发展前景进行了展望。     

生物高分子聚苹果酸及其衍生物的合成与应用前景

生物高分子对生命过程十分重要,它们表现出了卓越的特性和潜在的应用前景,因而一直是国内外学者的一个新的研究热点。聚苹果酸及其衍生物作为一类新型的生物高分子同样具有一些独特的性质。本文介绍了聚苹果酸及其衍生物的结构和性能特点,全面综述了它们的合成与制备方法研究的进展,展示了它们作为生物医用材料在药物释放体系、组织工程等领域中的应用前景。     

控制药物释放体系及其机理

药物控制释放是目前药物学发展的一个重要领域,用于药物控制释放的载体一般是高分子材料。本文主要介绍药物控制释放的种类、机理、高分子材料及其应用。     

聚合物/SiO2杂化材料在药物控制释放中的应用*

聚合物用作药物控制释放载体时,具有释药浓度可控、药物的生物利用率高、可实现靶向治疗等优点。但有些聚合物也存在机械强度低、化学稳定性差、生物相容性不理想等缺点。二氧化硅(SiO₂)具有多孔、无毒、生物相容性好、化学和机械稳定性高、表面易功能化等优点。但SiO₂用作药物控制释放载体时,有时也存在载药量低、不能装载大分子药物、不能实现靶向释放等缺点。聚合物/SiO₂杂化材料作为药物控制释放载体,可有效结合二者的优点,并克服二者的缺陷。根据聚合物的种类和杂化体系性质的不同,我们分别对温敏性聚合物/SiO₂杂化材料、聚电解质/SiO₂杂化材料、生物高分子/SiO₂杂化材料以及其它一些聚合物/SiO₂杂化材料体系在药物控制释放中的应用进行了介绍,并展望了该领域今后的研究发展方向。     

药物控制释放用天然多糖载体的制备技术研究进展

药物的控制释放体系是生物医用材料研究领域的重要课题,其支撑点是要有性能良好的高分子药物载体。由于天然多糖作为药物控制释放材料具有比合成聚合物更多的优势,因而一直是国内外学者研究的重点。文章从微球与胶囊、水凝胶、压缩膜三方面分别对天然多糖药物载体的制备技术进行了简述,并提出了多糖研究中存在的主要问题和今后的研究重点。     

高分子前药研究进展

高分子前药可以控制药物释放速度,降低小分子药物的毒副作用,减少抗药性,增强抗肿瘤药物的靶向性和选择性,提高多肽、蛋白质和核酸类药物的稳定性和有效利用率,引起国内外广泛关注.本文综述了近年来高分子药物的研究进展,主要从高分子载体材料的选择与改性对载药量、生物相容性和肾排泄的影响,以及化学合成过程中载体和药物末端的修饰、空...     

应用于药物控释系统中的生物降解高分子材料

生物降解高分子材料具有良好的生物相容性和生物降解性而成为人们关注的药物控释材料。本文简要介绍了生物降解高分子材料的降解机理，综述了生物降解高分子材料的发展现状，展望了今后的发展方向。     

左旋18—甲基炔诺酮—硅橡胶缓释体系小角激光散射法研究

以小角激光前向散射和背散射法研究了左旋１８－甲基炔诺酮－甲基乙烯基硅橡胶缓释体系的光散射时效行为，用紫外分光光度法测定释放过程，讨论药物释放过程中高分子链段运动和聚合物结构对药物释放的影响．     

Control of release kinetics of macromolecules from polymers

Internal and external means for controlling the release rates of large molecules, such as proteins, from ethylene—vinyl acetate copolymer matrices are presented. Internal approaches include alteration of the polymer—drug design, such as changing drug loading and particle size, coating the matrix, or altering matrix geometry. Kinetic and microstructural analyses are discussed. Applications of these polymeric systems, for instance, in delivery of insulin for diabetes, improved immunization procedures, and in developing bioassays for informational macromolecules are considered. In addition, a new approach for externally controlling release rates of drugs using magnetism has been developed. Until now, drug delivery systems were capable of delivering drugs at either constant or decreasing rates. We sought a system that permitted delivery of increased doses on demand, and achieved this by incorporating magnetic particles and drugs into polymeric matrices. Drug release rates can then be increased by an appropriate application of an external magnetic field. Over a five-day period, the magnetic field was applied ten times and drug release rates increased by up to 100% each time. Initial results indicate that this system does not cause tissue damage.     

Novel Antiretroviral Therapeutic Strategies for HIV

When the first cases of HIV infection appeared in the 1980s, AIDS was a deadly disease without any therapeutic alternatives. Currently, there is still no cure for most cases mainly due to the multiple tissues that act as a reservoir for this virus besides the high viral mutagenesis that leads to an antiretroviral drug resistance. Throughout the years, multiple drugs with specific mechanisms of action on distinct targets have been approved. In this review, the most recent phase III clinical studies and other research therapies as advanced antiretroviral nanodelivery systems will be here discussed. Although the combined antiretroviral therapy is effective in reducing viral loading to undetectable levels, it also presents some disadvantages, such as usual side effects, high frequency of administration, and the possibility of drug resistance. Therefore, several new drugs, delivery systems, and vaccines have been tested in pre-clinical and clinical trials. Regarding drug delivery, an attempt to change the route of administration of some conventional antiretrovirals has proven to be successful and surpassed some issues related to patient compliance. Nanotechnology has brought a new approach to overcoming certain obstacles of formulation design including drug solubility and biodistribution. Overall, the encapsulation of antiretroviral drugs into nanosystems has shown improved drug release and pharmacokinetic profile.     

Synthetic and natural polymers as drug carriers for tuberculosis treatment

Drug forms based polymer carriers of prolong action were created for toxicologic effect of drug to be reduced in spite of long treatment of diseases. In present work a number of synthesis and natural polymers have been studied as carriers of antituberculous drugs for controlled delivery application. Following as drugs as isoniazid and ethionamide were incorporated into polymeric matrix (segmented polyurethanes, polyvinyl alcohol) and chemically bound with the polymer chain by covalent or electrostatic forces (aldehyde- and carboxymethylderivatives of polysaccharides). Biodegradation of polymeric systems and the release of drugs were studied by various physico-chemical methods. It was shown that the drug release depends of method of the immobilization, type of the drug/polymer bonding, drug loading. The bacteriostatic activity of obtained systems was determined. The possibility of tuberculosis treatment was proved in experiments of animals.     

Polymeric microspheres: a delivery system for osteogenic differentiation

Advanced drug delivery systems employing controlled release technology are being developed to address many of the difficulties associated with traditional methods of drug administration. Controlled release technology involves the use of devices such as polymer‐based disks, rods, pellets, or microspheres (MSs) that encapsulate drugs, genes, cytokines, and growth factors and release them in specific location within the body in a controlled fashion, for relatively long periods of time. Among these, microencapsulation is one of the core technologies used in polymer‐based drug delivery systems. In this regard, MS serves as microcarriers for sustain drug release facilitating their use for invasive or minimally invasive treatment. MS has significant potential for the application in bone repair, intra‐articular treatment of osteoarthritis, and biological bone growth. The present review compiles the recent advances in polymeric MS for application in bone and cartilage regeneration. Copyright © 2017 John Wiley & Sons, Ltd.     

DNA纳米结构在药物转运载体和智能载药中的应用进展

纳米材料具有荷载效率高、靶向性能好、半衰期较长等优点, 非常适于作为药物转运载体, 可有效提高药物的水溶性、稳定性和疾病治疗效果.目前, 开发具有良好生物相容性、可控靶向释放能力和精确载药位点的理想药物转运载体, 仍是该领域存在的挑战性问题和当前研究的重点.自组装DNA纳米结构是一类具有精确结构、功能多样的纳米生物材料, 具有良好的生物相容性和稳定性、较高的膜渗透性和可控靶向释放能力等优点, 是理想的药物转运载体和智能载药材料.本文总结了DNA纳米结构的发展历程、DNA纳米结构作为药物转运载体的研究现状、动态DNA纳米结构在智能载药中的应用进展, 并对其发展前景进行了展望.     

基于透明质酸的刺激响应纳米给药系统的研究进展

透明质酸(Hyaluronic acid, HA)是一种天然多糖,具有良好的生物相容性和生物降解性,利用 HA 构建的纳米载体自身就具有肿瘤靶向功能,可以作为抗癌药物载体将药物传递到肿瘤细胞内从而实现精准到达病患处。近年来透明质酸在应用于肿瘤靶向给药系统中的关注越来越多,成为了靶向治疗肿瘤的一大研究热点。基于透明质酸的基本特性和肿瘤靶向的生理学基础,在不同的刺激响应下,透明质酸型纳米给药系统能将药物集中释放于肿瘤的微环境内,更好地杀死肿瘤细胞,同时避免其他正常的组织受到药物损害。本文主要综述了透明质酸型纳米药物输送系统在各种刺激响应下释放药物的最新研究进展。     

Nanostructures for magnetically triggered release of drugs and biomolecules

Specific targeting and controlled release are crucial factors in the administration of drugs and therapeutic biomolecules. It has been shown that drug delivery systems can significantly benefit of the introduction of superparamagnetic nanoparticles in terms of both targeting and controlled release. Magnetic gradients can be used to target therapeutics to specific regions, while alternating magnetic fields produce frequency-dependent effects at the nanoparticle level. This review reports on the latest developments of multifunctional systems based on magnetic nanoparticles where the release of drugs and/or biomolecules is triggered by the application of an external magnetic field. The potentials of these systems are presented through examples in the fields of surface functionalized magnetic nanoparticles, magnetic polymer nanocomposites and magnetoliposomes. Recent results suggest the importance of integrating multiple functions within a single nanostructured device in order to successfully transport, localize and release drugs and biomolecules.     

壳聚糖/乙酰半胱氨酸纳米粒子的性质及体外释药性

制备了一种基于壳聚糖/乙酰半胱氨酸偶合物(CS-NAC)的新型巯基纳米粒子并进行了结构表征, 同时对纳米粒子的黏附性、溶胀性和药物释放进行了测试. 结果表明, 纳米粒子具有较小的粒径(140~210 nm)和正的表面电位(19.5~31.7 mV), 胰岛素的载药量达到13%~42%. 这些性质随着巯基含量的变化而变化. 与壳聚糖纳米粒子相比, 巯基壳聚糖纳米粒子表现出了更强更快的黏附性质. 体外释放研究结果表明, 巯基壳聚糖纳米粒子的胰岛素释放具有pH响应性. 在pH=6.8时, 15 min即能释放58.6 %的胰岛素; 而在pH=5.4时, 24 h内仅有不到40%的胰岛素被释放. 因此, CS-NAC纳米粒子用于胰岛素的黏膜给药体系具有很好的应用前景.     

Progress in natural polymer engineered biomaterials for transdermal drug delivery systems

The route of a specific drug carrier system is always a significant platform of development that combines the principles of biomedical technology, nanotechnology, and pharmaceutical drug design. Transdermal (TD) drug delivery involves the release of the drug via the stratum corneum of the tissue membrane into the sustained release by diffusion across the epidermal layer. This method (often known as topical drug delivery) has increased noteworthy research enthusiasm in the course of recent decades due to its relatively simpler and non-invasive administration. Over the past few decades, considerable advancement was achieved in TD delivery and a number of drugs are now successfully reported. In this review, we focus on the progress regarding applications of important biopolymers described for the TD drug release applications and related aspects. Three mostly reported plant and animal-derived polymers (such as natural rubber, chitosan, and cellulose for the development of TD carrier system) were extensively analyzed. The general principle of TD drug delivery, advantages, and limitations of the works reported were also discussed.     

Physicochemical aspects of drug delivery and release from polymer-based colloids

Recent advances in the preparation/loading, surface properties, and applications of polymer-based colloidal drug delivery and release systems, such as block copolymer micelles, polymer nano- and microparticles, polymer-modified liposomes, and chemical and physical hydrogels are presented. Drug release from polymer-based systems is affected by the drug–polymer interactions as well as the polymer microstructure and dissociation/erosion properties. Surface modification with poly(ethylene oxide) has become common in improving the biocompatibility and biodistribution of drug delivery carriers. Site-specific drug delivery can be achieved by polymer-based colloidal drug carriers when ligands of targeting information are attached on the carrier surface or when a phase transition is induced by an external stimulus. While significant progress in being made, many challenges remain in preserving the biological activity and attaining the desired drug release properties, especially for protein and DNA drugs.