可溶性聚合物微针在眼部疾病药物递送中的应用研究进展

由于眼球特殊解剖结构和生理屏障的限制, 眼部疾病的药物递送极具挑战。眼部药物的传统给药方式普遍存在药物生物利用度低、缺乏组织靶向性等不足, 需多次给药以达到理想的药物治疗浓度。由于具备安全、微创、高效等特点, 微针近年来已被广泛应用于眼部药物递送的研究。而可溶性聚合物微针作为微针中的一大类, 因其相较于其他类型微针的独特优势已成为眼部给药领域研究热点。基于此, 本文对可溶性聚合物微针在眼部疾病药物递送中的应用研究进展进行总结和展望。     

微针药物递送系统应用于角膜病治疗的研究进展

角膜病是我国常见的眼部疾病之一, 短期内得不到有效救治很容易致盲。然而, 由于眼部屏障和清除机制的存在, 安全有效地将药物输送到角膜十分具有挑战性。传统给药方式生物利用度低, 难以达到治疗效果。微针能够有效穿过眼表屏障, 将药物顺利递送至靶部位, 且侵入性小, 是目前最具有潜力的穿透性给药技术。本文介绍了眼表的主要递送屏障, 微针的分类以及在角膜疾病治疗领域的最新进展。最后, 对微针递送系统应用于眼表的潜在挑战进行了分析, 以期为微针在角膜疾病中的临床应用提供参考。     

眼用给药系统的研究进展

由于眼部生理结构复杂和诸多屏障的存在，许多药物对眼部疾病的治疗作用甚微。为了更好地使治疗药物进入眼内发挥疗效，眼部给药的途径也是药剂学研究的热点之一。本文就近年来凝胶系统、胶粒系统、微粒系统、植入剂等眼用给药途径的研究进展作一综述。     

纳米材料药物传输载体在治疗眼病中的应用

由于眼表面和眼内结构的解剖、生理屏障作用,常规眼部制剂一般无法到达特定位置发挥作用.纳米材料由于尺寸小、易制备、可降解、靶向性强以及对生物组织刺激性小等特点,不同类型的纳米材料在运载不同化学特性药物方面优势明显.目前,纳米材料作为药物传输载体在眼部给药方面应用越来越多,并被用于各种类型眼部疾病的治疗,显示出良好的应用前景.本文就纳米材料作为药物传输载体在眼科疾病治疗方面的应用作一综述.     

基于角膜接触镜的眼部长效给药技术研究进展

传统眼用制剂如滴眼液等存在药物利用率低、患者依从性差等问题。用于视力矫正的角膜接触镜(CL)具有良好的生物相容性和长期配戴舒适度,并能延长药物停留时间、提高生物利用度,成为很有前景的眼部给药载体。为了提高CL的药物负载量并延长药物释放时间,研究者开发了多种策略对传统CL进行改良,包括引入维生素E分子屏障,基于分子印迹技术制备CL,引入特定基团以增加药物与聚合物基质之间的相互作用,负载胶体纳米颗粒或载药聚合物薄膜等。本文综述了载药CL的各种制备方法及其优缺点,并简要评述了CL作为眼部药物递送载体存在的问题及未来发展方向。     

眼用药物缓释载体的研究进展

由于眼部的生理结构复杂和诸多屏障的存在,许多药物在眼科的临床应用受到限制.为了使药物在眼部更好地发挥药效,新型给药方法和技术的探索成为研究热点.近年出现的眼科药物缓释系统包括:(1)药胶粒系统如脂质体、微乳等;(2)微粒系统如微球、纳米粒、固体脂质纳米粒和纳米结构脂质载体等;(3)凝胶系统包括生物黏附性凝胶、原位凝胶等;(4)眼部植入系统包括插入剂和眼内植入剂等.     

纳米给药系统在眼科的应用

纳米颗粒是纳米尺寸范围内的胶体载药系统,具有靶向、控释和跨生物膜给药等特点,可有效提高药物在眼部的生物利用度。研究发现,纳米制剂眼表给药在青光眼、眼内炎症和感染等治疗方面有极大的应用潜力。     

纳米控释系统在眼科给药方面应用的研究进展

纳米材料在眼部给药方面的应用主要集中在纳米控释系统,由于纳米材料的特有属性,使用纳米材料运载治疗眼部疾病的药物与传统给药方式相比具有很大的优越性,主要表现在药物的纳米制剂具有更高的生物利用率和更低的副作用。因此纳米控释系统在眼科具有良好的应用前景。目前,已经有多种不同类型的纳米控释系统被用于提高眼部给药效率的研究,包括纳米胶束、纳米颗粒、纳米混悬剂、脂质体和树突状分子等。本文就纳米控释系统在眼科给药方面应用的研究进展作一综述。     

玻璃体腔内植入装置在玻璃体视网膜疾病的临床应用

因血-视网膜屏障的存在,玻璃体视网膜疾病的给药方法常受到限制,玻璃体腔内注射药物直接作用于玻璃体和视网膜,是其有效治疗方法,但对慢性反复发作性疾病,需频繁注射以达到有效药物浓度。玻璃体腔内植入装置既避开了血-视网膜屏障,又延长了药物的作用时间,是治疗玻璃体视网膜疾病的新方法,因其装载的药物不同而治疗不同的疾病。抗病毒药物植入装置能有效治疗获得性免疫缺陷综合征患者的巨细胞病毒性视网膜炎。激素类植入装置能有效治疗眼底慢性炎性疾病如黄斑水肿、非感染性葡萄膜炎,主要副作用为眼压升高和白内障形成。睫状神经营养因子和抗血管内皮生长因子植入装置可能是老年性黄斑变性的有效治疗药物。本文将综述目前常见的玻璃体腔内植入装置在玻璃体视网膜疾病中的临床应用。     

左氧氟沙星眼用凝胶剂的兔眼药物动力学及生物利用度的研究

由于泪液的流动使得眼部用抗生素的生物利用度降低，加之角膜上皮的屏障作用，使用眼液滴眼的方法可能无法获得有效的药物治疗浓度。通过改善给药系统可延长抗菌药物与角膜组织的接触时间，改善药物的眼内通透性。     

眼内缓释给药的研究现状

药物疗法是防治多种眼内增生性、感染性和变性疾病的重要措施之一，而眼内缓释给药系统是实现高效、低毒局部药物治疗的一种有效手段。近年来有关眼内缓释给药系统的研究包括脂质体、纳米粒、微粒体、植入体和巩膜塞等。离子电渗给药作为一种物理控释给药途径也受到关注。[眼科新进展2005；25（5）：464—466]     

葡萄膜炎的缓释治疗给药研究进展

葡萄膜炎病因繁多,发生机制复杂,感染、自身免疫及各种理化和机械损伤因素等均可引起,治疗较为棘手,未得到及时有效治疗常可导致失明。随着人们对葡萄膜炎及其相关机制认识的加深,各种新型的葡萄膜炎缓释治疗给药系统被研究,但是,由于眼部各种解剖学和生理学屏障的存在,使得葡萄膜炎的缓释治疗存在多重阻碍。本文综述了该领域近年来的主要研究成果,讨论了各新型缓释给药系统的创新点和局限性,以期能为未来葡萄膜炎的缓释给药治疗提供新思路。这些新型缓释给药系统有助于在未来彻底改变葡萄膜炎治疗副作用大、依从性差的传统治疗模式,带来更长时间的靶向缓释和更少的毒性反应。     

Nanoparticles in the ocular drug delivery

Ocular drug transport barriers pose a challenge for drug delivery comprising the ocular surface epithelium, the tear film and internal barriers of the blood-aqueous and blood-retina barriers. Ocular drug delivery efficiency depends on the barriers and the clearance from the choroidal, conjunctival vessels and lymphatic. Traditional drug administration reduces the clinical efficacy especially for poor water soluble molecules and for the posterior segment of the eye. Nanoparticles (NPs) have been designed to overcome the barriers, increase the drug penetration at the target site and prolong the drug levels by few internals of drug administrations in lower doses without any toxicity compared to the conventional eye drops. With the aid of high specificity and multifunctionality, DNA NPs can be resulted in higher transfection efficiency for gene therapy. NPs could target at cornea, retina and choroid by surficial applications and intravitreal injection. This review is concerned with recent findings and applications of NPs drug delivery systems for the treatment of different eye diseases.     

Nanomedicine in the application of uveal melanoma

Rapid advances in nanomedicine have significantly changed many aspects of nanoparticle application to the eye including areas of diagnosis, imaging and more importantly drug delivery. The nanoparticle-based drug delivery systems has provided a solution to various drug solubility-related problems in ophthalmology treatment. Nanostructured compounds could be used to achieve local ocular delivery with minimal unwanted systematic side effects produced by taking advantage of the phagocyte system. In addition, the in vivo control release by nanomaterials encapsulated drugs provides prolong exposure of the compound in the body. Furthermore, certain nanoparticles can overcome important body barriers including the blood-retinal barrier as well as the corneal-retinal barrier of the eye for effective delivery of the drug. In summary, the nanotechnology based drug delivery system may serve as an important tool for uveal melanoma treatment.     

Nanomedicines for back of the eye drug delivery,gene delivery,and imaging

Treatment and management of diseases of the posterior segment of the eye such as diabetic retinopathy, retinoblastoma, retinitis pigmentosa, and choroidal neovascularization is a challenging task due to the anatomy and physiology of ocular barriers. For instance, traditional routes of drug delivery for therapeutic treatment are hindered by poor intraocular penetration and/or rapid ocular elimination. One possible approach to improve ocular therapy is to employ nanotechnology. Nanomedicines, products of nanotechnology, having at least one dimension in the nanoscale include nanoparticles, micelles, nanotubes, and dendrimers, with and without targeting ligands. Nanomedicines are making a significant impact in the fields of ocular drug delivery, gene delivery, and imaging, the focus of this review. Key applications of nanotechnology discussed in this review include a) bioadhesive nanomedicines; b) functionalized nanomedicines that enhance target recognition and/or cell entry; c) nanomedicines capable of controlled release of the payload; d) nanomedicines capable of enhancing gene transfection and duration of transfection; f) nanomedicines responsive to stimuli including light, heat, ultrasound, electrical signals, pH, and oxidative stress; g) diversely sized and colored nanoparticles for imaging, and h) nanowires for retinal prostheses. Additionally, nanofabricated delivery systems including implants, films, microparticles, and nanoparticles are described. Although the above nanomedicines may be administered by various routes including topical, intravitreal, intravenous, transscleral, suprachoroidal, and subretinal routes, each nanomedicine should be tailored for the disease, drug, and site of administration. In addition to the nature of materials used in nanomedicine design, depending on the site of nanomedicine administration, clearance and toxicity are expected to differ.     

Electrically assisted ocular gene therapy

Electrotransfer and iontophoresis are being developed as innovative non-viral gene delivery systems for the treatment of eye diseases. These two techniques rely on the use of electric current to allow for higher transfection yield of various ocular cell types in vivo. Short pulses of relatively high-intensity electric fields are used for electrotransfer delivery, whereas the iontophoresis technique is based on the application of low voltage electric current. The basic principles of these techniques and their potential therapeutic application for diseases of the anterior and posterior segments of the eye are reviewed. Iontophoresis has been found most efficient for the delivery of small nucleic acid fragments such as antisense oligonucleotides, siRNA, or ribozymes. Electrotransfer, on the other hand, is being developed for the delivery of oligonucleotides or custom designed plasmids. The wide range of strategies already validated and the potential for targeting specific types of cells confirm the promising early observations made using electrotransfer and iontophoresis. These two nonviral delivery systems are safe and can be used efficiently for targeted gene delivery to ocular tissues in vivo. At the present, their application for the treatment of ocular human diseases is nearing its final stages of adaptation and practical implementation at the bedside.     

Transport barriers in transscleral drug delivery for retinal diseases

Transscleral delivery has emerged as an attractive method for treating retinal disorders because it offers localized delivery of drugs as a less invasive method compared to intravitreal administration. Numerous novel transscleral drug delivery systems ranging from microparticles to implants have been reported. However, transscleral delivery is currently not as clinically effective as intravitreal delivery in the treatment of retinal diseases. Transscleral drug delivery systems require drugs to permeate through several layers of ocular tissue (sclera, Bruch's membrane-choroid, retinal pigment epithelium) to reach the neuroretina. As a result, a steep drug concentration gradient from the sclera to the retina is established, and very low concentrations of drug are detected in the retina. This steep gradient is created by the barriers to transport that hinder drug molecules from successfully reaching the retina. A review of the literature reveals 3 types of barriers hindering transscleral drug delivery: static, dynamic and metabolic. While static barriers have been examined in detail, the literature on dynamic and metabolic barriers is lacking. These barriers must be investigated further to gain a more complete understanding of the transport barriers involved in transscleral drug delivery.     

Nanostructure-based platforms-current prospective in ophthalmic drug delivery

The topically applied drugs as drops are washed off from the eye in very short period, resulting in low ocular bioavailability of drugs. Number of approaches have been attempted to increase the bioavailability and the duration of action of ocular drugs. This review provides an insight into various novel approaches; hydrophilic nanogels, solid lipid nanoparticles, and nanosponges applied very recently in the delivery of insoluble drugs, prolonging the ocular residence time, minimize pre-corneal drug loss and, therefore, bioavailability and therapeutic efficacy of the drugs. Despite various scientific approaches, efficient ocular drug delivery remains a challenge for pharmaceutical scientists.