原位凝胶应用于眼部给药系统的研究进展

介绍原位凝胶在眼部给药系统中的研究新方法和新进展,以及原位凝胶的不同胶凝机理,分析胶化过程和眼部应用时的影响因素。原位凝胶滴眼剂可以显著延长药物释放,提高药物生物利用度。原位凝胶滴眼剂作为一种新型眼部药物新剂型,具有良好的应用前景。     

水凝胶基质在眼部给药系统的研究进展

目的：综述了水凝胶基质在眼部给药系统的研究进展。方法：通过查阅国内外文献总结了卡波姆、泊洛沙姆、羟丙基甲基纤维素、聚乙烯醇以及一些天然树胶等几种水凝胶基质的各自特点和应用，并对目前水凝胶基质眼部给药系统研发中存在的难点及其发展方向做了初步的分析。结果：水凝胶基质眼部给药系统的研发近年取得了长足的进展，在治疗眼部疾病中日益受到重视。结论：水凝胶具有眼部滞留时间长、无油腻感、生物相容性好以及安全性高等优点，是眼用制剂的良好基质，具有广阔的应用前景。     

眼部给药系统的研究进展

随着现代社会人口老龄化、眼病患者的增多。眼用制剂的使用呈现高速增长趋势。由于眼部的生理结构特殊,药物在眼部的生物利用度偏低。为了使治疗药物进入眼内发挥疗效,新型眼用给药系统是近年来医药市场研究和开发的热点。未来的眼科用药需要新型的给药系统如凝胶系统、微球毫微粒给药系统、植入剂、插入剂、眼用冻干载体系统等,其优势是：提高了药物的吸收率,减少给药次数,降低药物的不良反应,在局部给药系统中具有独特性。现将新型眼用给药系统的特性、研究的进展及发展趋势作一论述。新型给药系统虽还有一些问题有待解决,但却是一个很有发展潜力的给药系统。     

眼用凝胶给药系统研究进展

眼部给药剂型常采用滴眼液和眼膏,结膜囊内给药是最常见的药物治疗眼部疾病的方法。据统计,眼用制剂中溶液型滴眼剂占有60％以上的比例,因其使用方便,非侵入性,容易配方,顺应性好和价格低廉而容易被广大患者接受。但是随着生物药剂学和药物动力学的深入研究,发现常规滴眼液和眼膏存在眼部药物滞留时间短、生物利用度低（1％-10％）等问题,仅有少于5％的药物通过角膜到达眼内发挥治疗作用。这是由于眼睛具有流泪和眨眼反射等非常有效的保护机制,使滴入到眼内的药液迅速从角膜前区域消除。这大大影响了眼部给药的治疗效果。     

眼部给药系统的研究进展

介绍近年来眼部给药在胶粒系统、微粒系统、凝胶系统、眼部插入剂和植入剂以及给药装置等方面的研究进展和存在问题。与其它剂型相比，眼用制剂的发展相对比较缓慢，但在研究方面，依然在很多领域取得了进展。     

眼部给药体系研究进展

眼部药物释放对药学科学家来说是极富挑战性的领域.眼部特殊的组织解剖结构以及生理学、生化学特点决定了眼部外用药物的低渗透性,因此如何使药物更多更安全地进入眼内,是目前眼部用药领域的一个研究热点.传统的眼部给药剂型是局部用滴眼剂和眼膏剂,这两种常见剂型有配制容易、使用方便的优点,易于被患者接受.眼部用药后,药物的转运和流失受一系列的屏障和扩散限制,眼是一个相对独立的器官,具有自身屏障系统(泪液膜、巩膜、结膜、角膜等),并且药物滴人眼部的刺激性,致使泪液大量分泌[1].因此眼部用药后,大部分药物通过泪液排出系统和眼睑缝隙流失掉,此外角膜上皮的低通透性、血.眼屏障的阻碍,致使只有1％甚至更少剂量的药物通过角膜转运进入眼内到达眼前节.由于以上的因素,使得眼部药物的生物利用度很低,因此,设计具有一定缓释作用的眼部给药新剂型,延长药物的眼部滞留时间,降低刺激性,是当前眼部给药剂型研究的方向.本文就眼部给药体系研究的进展进行综述.     

眼部给药系统的研究进展

目的 介绍眼部给药系统的研究进展。方法 查阅总结近年来眼部给药系统的最新研究成果,展望其发展前景。结果 胶粒给药系统使不同阶段眼部疾病的治疗成为可能;靶向给药使得药物能够透过各种屏障到达眼部病变部位;原位凝胶显著延长了药物在眼部的滞留时间;可降解植入剂避免了释药后的二次手术;眼部电离子渗透技术大大降低了眼部治疗的创伤。结论 随着临床医学、药物制剂学、高分子材料学的发展及新技术的应用,眼部给药系统在眼部疾病治疗中的应用更加广泛,具有很好的发展前景。     

眼部给药系统的研究进展

目的介绍眼部给药系统的研究进展。方法查阅总结近年来眼部给药系统的最新研究成果,展望其发展前景。结果胶粒给药系统使不同阶段眼部疾病的治疗成为可能;靶向给药使得药物能够透过各种屏障到达眼部病变部位;原位凝胶显著延长了药物在眼部的滞留时间;可降解植入剂避免了释药后的二次手术;眼部电离子渗透技术大大降低了眼部治疗的创伤。结论随着临床医学、药物制剂学、高分子材料学的发展及新技术的应用,眼部给药系统在眼部疾病治疗中的应用更加广泛,具有很好的发展前景。     

眼部给药途径的研究进展

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、微粒、胶粒、注射、植入等眼部给药途径的研究进展做一综述。     

高分子载体材料应用于眼部给药系统的研究进展

随着现代社会生活水平的提高、人口老龄化、眼疾患者的增加和眼部保健要求的提高,眼用药物的研究开发正呈现高速增长的趋势。本文综述了近几年来高分子载体材料在眼科中的应用,为研究者进行眼部给药系统的研究提供理论依据。     

Ion- and pH-activated novel in-situ gel system for sustained ocular drug delivery

Poor bioavailability (<1%) of drugs from conventional eye drops is mainly due to the various precorneal loss factors which include rapid tear turnover, systemic drug absorption through naso-lachrymal duct, transient residence time of the drug solution in the cul-de-sac and the relative impermeability of the drugs to corneal epithelial membrane. The present study describes the formulation and evaluation of chitosan and gellan gum based novel in-situ gel system activated by dual physiological mechanisms. Chitosan (a pH-sensitive polymer) in combination with gellan gum (an ion-activated polymer) were used as gelling agent. Timolol maleate, the drug which is frequently used for glaucoma therapy was used as model drug to check the efficacy of the formulation. The developed formulation was characterized for various in vitro parameters, for example, clarity, gelation pH, isotonicity, sterility, viscosity, transcorneal permeation profile, and ocular irritation. Ocular retention was studied by gamma scintigraphy and a significant increase in retention time was observed. The formulation was also found to be nonirritant and well tolerable. The developed system can be a viable alternative to conventional eye drops for the treatment of various ocular diseases and is suitable for clinical application.     

Research progress of in-situ gelling ophthalmic drug delivery system

 Blindness and vision impairment are the most devastating global health problems resulting in a substantial economic and social burden. Delivery of drug to particular parts of the anterior or posterior segment has been a major challenge due to various protective barriers and elimination mechanisms associated with the unique anatomical and physiological nature of the ocular system. Drug administration to the eye by conventional delivery systems results in poor ocular bioavailability (<5%). The designing of a novel approach for a safe, simple, and effective ocular drug delivery is a major concern and requires innovative strategies to combat the problem. Over the past decades, several novel approaches involving different strategies have been developed to improve the ocular delivery system. Among these, the ophthalmic in-situ gel has attained a great attention over the past few years. This review discussed and summarized the recent and the promising research progress of in-situ gelling in ocular drug delivery system.     

Minimally invasive microneedles for ocular drug delivery

Introduction: Anterior and posterior segment eye diseases are highly challenging to treat, due to the barrier properties and relative inaccessibility of the ocular tissues. Topical eye drops and systemically delivered treatments result in low bioavailability. Alternatively, direct injection of medication into the ocular tissues is clinically employed to overcome the barrier properties, but injections cause significant tissue damage and are associated with a number of untoward side effects and poor patient compliance. Microneedles (MNs) has been recently introduced as a minimally invasive means for localizing drug formulation within the target ocular tissues with greater precision and accuracy than the hypodermic needles.

Areas covered: This review article seeks to provide an overview of a range of challenges that are often faced to achieve efficient ocular drug levels within targeted tissue(s) of the eye. It also describes the problems encountered using conventional hypodermic needle-based ocular injections for anterior and posterior segment drug delivery. It discusses research carried out in the field of MNs, to date.

Expert opinion: MNs can aid in localization of drug delivery systems within the selected ocular tissue. And, hold the potential to revolutionize the way drug formulations are administered to the eye. However, the current limitations and challenges of MNs application warrant further research in this field to enable its widespread clinical application.     

A review on therapeutic contact lenses for ocular drug delivery

Contact lenses for ophthalmic drug delivery have become very popular, due to their unique advantages like extended wear and more than 50% bioavailability. To achieve controlled and sustained drug delivery from contact lenses, researchers are working on various systems like polymeric nanoparticles, microemulsion, micelle, liposomes, use of vitamin E, etc. Numerous scientists are working on different areas of therapeutic contact lenses to treat ocular diseases by implementing techniques like soaking method, molecular imprinting, entrapment of drug-laden colloidal nanoparticles, drug plate/film, ion ligand polymeric systems, supercritical fluid technology, etc. Though sustained drug delivery was achieved using contact lens, the critical properties such as water content, tensile strength (mechanical properties), ion permeability, transparency and oxygen permeability were altered, which limit the commercialization of therapeutic contact lenses. Also issues like drug stability during processing/fabrication (drug integrity test), zero order release kinetics (prevent burst release), drug release during monomer extraction step after fabrication (to remove un-reacted monomers), protein adherence, drug release during storage in packaging solution, shelf life study, cost-benefit analysis, etc. are still to be addressed. This review provides an expert opinion on different methodology to develop therapeutic contact lenses with special remark of their advantages and limitations.     

pH敏感型盐酸左氧氟沙星眼用即型凝胶的制备及其体外释放考察

目的研制具有缓释作用的pH敏感型盐酸左氧氟沙星眼用即型凝胶。方法以卡波普为凝胶基质,以羟丙甲基纤维素为增稠剂,以溶液的粘度、即型凝胶形成能力及盐酸左氧氟沙星含量为评价指标,确定制备处方和工艺,并以优选处方进行体外释放考察。结果经实验,其优选处方为盐酸左氧氟沙星0.1 g,羟丙甲基纤维素E 50 LV 2.0 g,卡波普9 400.3g,磷酸氢二钠0.35 g,磷酸二氢钠0.45 g,氯化钠0.50 g,尼泊金乙酯0.03 g,加水共制成100 ml。体外释放结果显示其释药平缓,具有较好的缓释特征。结论优选处方工艺稳定,质量控制方法可靠,适用于pH敏感型盐酸左氧氟沙星眼用即型凝胶的制备和评价。     

经鼻脑靶向递药系统的研究进展

鼻腔与脑在解剖生理上的独特联系使得鼻腔给药作为脑内递药途径成为可能.鼻腔给药作为脑靶向的途径之一,可有效地使通过其他给药途径不易透过血脑屏障的药物绕过血脑屏障到达脑部,为中枢神经系统疾病的治疗提供了一种极有发展前景的脑内递药途径.就鼻腔给药脑靶向的依据、影响因素、评价方法、剂型等方面对经鼻脑靶向递药系统的研究现状进行总结.     

肝靶向给药系统的研究进展

通过对近年来国内外报道的肝靶向研究相关文献进行检索,根据肝靶向药物的不同作用机制对肝靶向给药系统的研究进展进行分析和总结。有关肝靶向药物的研究结果表明,肝靶向给药系统能选择性地将药物输送至肝脏病变部位,通过提高其在肝脏病变组织的药物浓度,从而达到增强药物疗效、减少其毒副作用的目的。因此,肝靶向给药系统在肝脏疾病治疗方面具有广阔的应用前景。     

新型药物凝胶剂研究进展

新型药物凝胶剂是近年来兴起的一种新剂型,其在医药领域的应用研究逐渐引起关注。笔者概述其几种常见类型,如智能型水凝胶剂、脂质体凝胶剂、包合物凝胶剂,望为这方面的研究提供参考。     

靶向制剂研究进展

靶向制剂具有提高靶组织的药理作用强度和控制释药,恒定血药浓度,降低全身的不良反应等鲜明特点,是一种较理想的给药方式,因此靶向给药系统(TDDS)已成为现代药剂学的重要研究热点之一.本文就靶向制剂的研究近况及其进展进行概括.