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。     

聚合物在温度敏感型原位凝胶中的应用

多种聚合物可用于原位凝胶系统,使其随温度的变化而胶凝,缓慢持久地释放药物,在临床上有着广阔的应用前景。聚合物的开发应用必将不断地促进温度敏感型原位凝胶的快速发展。     

温度敏感型原位凝胶用于蛋白类药物缓释注射给药系统的初步研究

尝试以温度敏感型原位凝胶（TISG）作为重组人生长激素（rhGH）的载体制备缓释注射给药系统，通过改变泊洛沙姆同系物的配比，得到了具有适宜胶凝温度的TISG，并采用无膜溶出模型研究了TISG的体外释药行为。结果表明，rhGH从TISG中的释放遵循零级动力学过程，且胶凝温度接近体温的TISG维持释放的时间较短。大鼠体内实验进一步证实，TISG可延缓rhGH释放，与溶液制剂相比可获得更平缓且持久的血药浓度曲线。     

原位凝胶应用于眼部给药研究进展

眼用原位凝胶具有独特的作用特点及优势,能显著提高药物的生物利用度。本文从眼用原位凝胶的分类、特点等方面进行了详细的介绍,并总结近年来国内外相关文献资料。作为一种新型制剂,眼用即型凝胶具有广阔应用前景。在眼部给药领域必将得到越来越多的关注和研究。     

瘀肿消温度敏感型原位凝胶的基质配比优选

目的优选瘀肿消温度敏感型原位凝胶的基质配比。方法以温度敏感型原位凝胶的胶凝温度、胶凝强度、生物黏附力为考察指标,优选出瘀肿消温度敏感型原位凝胶基质配比。结果瘀肿消温度敏感型原位凝胶基质配方Poloxamer407、Poloxamer188、卡波姆分别为22%、3%、0.7%。结论瘀肿消温度敏感型原位凝胶成型工艺简单、性质稳定。     

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。     

喷昔洛韦眼用温度敏感原位凝胶的制备及评价（英文）

目的研制以普朗尼克F127为主要基质的喷昔洛韦制剂,以提高其眼部生物利用度。方法通过将HPMC K4M或卡波姆934P与普朗尼克F127复合使用,制备了喷昔洛韦的温度敏感原位凝胶。以胶凝温度、流变学、药物释放特性、药代动力学及眼部刺激性等为指标进行筛选,得到最优化处方。结果使用HPMC K4M或者卡波姆934P均能降低凝胶的胶凝温度,略微增加其粘度,延缓体系中药物的释放速率;药物释放为非Fick扩散;所有处方均未表现出眼部刺激或对角膜的损伤;含卡波姆934P和普朗尼克F127的凝胶体系的眼部生物利用度最高。结论含普朗尼克F127的喷昔洛韦制剂能够以滴眼液的形式给药,而达到眼部温度时可形成凝胶;体内外评价结果表明,含有HPMC K4M或卡波姆934P以及低浓度普朗尼克F127（12%）的喷昔洛韦制剂,提高了药物在眼部的生物利用度,是一种很有前景的眼部给药系统。     

奥洛他定温度敏感眼用原位凝胶的制备

目的:研制奥洛他定温度敏感眼用原位凝胶。方法:采用泊洛沙姆P407和P188为温敏材料,以胶凝温度为指标,通过星点设计-效应面法优化处方。结果:经过优化筛选出的处方在室温条件下是自由流动的液体,在生理条件下发生胶凝形成凝胶。结论:所研制奥洛他定眼用温度敏感原位凝胶符合眼部应用要求,体现出良好的临床应用前景。     

地塞米松磷酸钠温度敏感原位凝胶的特性研究

本文以泊罗沙姆PluronicF127为温度敏感原位凝胶材料，考察了PluronicF127与PluronicF68不同浓度处方对地塞米松磷酸钠温度敏感原位凝胶的胶凝温度、相转变温度、凝胶强度、稳态黏度、溶蚀和药物释放行为等特性的影响。采用试管倒转法测定胶凝温度；旋转流变仪测定相转变温度、弹性模量、稳态黏度等流变学参数；无膜溶出法测定凝胶的溶蚀行为；HPLC测定地塞米松磷酸钠的释放度。结果表明，随着处方中F127浓度的增高，凝胶的胶凝温度和相转变温度降低，黏度和弹性模量增加，溶蚀速率和药物释放速率减慢；而处方中F68对凝胶特性的影响与F127相反。温度敏感原位凝胶在低温时为牛顿流体，黏度很小；随着温度升高，黏度增大；当增至相转变温度附近，表现出典型的假塑性流体特征；药物释放速率受控于凝胶溶蚀速率，二者遵循零级动力学方程。处方中含F127 22.5% / F68 2.5%的地塞米松磷酸钠温度敏感原位凝胶的性质与临床治疗要求基本吻合，有望在临床中获得应用。     

蒲公英眼用温敏凝胶的制备

目的研究蒲公英眼用温敏凝胶的制备工艺。方法以泊洛沙姆407、泊洛沙姆188、HPMC为混合凝胶基质,以泪液稀释前后的胶凝温度为指标,采用均匀设计法设计蒲公英眼用温敏凝胶的处方。结果该制剂在室温条件下是自由流动的液体,在生理条件下发生相变形成凝胶,符合眼用制剂的质量要求;凝胶溶蚀控制药物的释放速率,二者均遵循零级动力学方程。结论蒲公英眼用温敏凝胶的制备工艺简单、可行。     

眼部给药系统及影响因素

目的 对眼部给药系统及影响因素进行综述.方法 查阅文献,总结近年来眼部给药系统的最新研究成果、影响眼部给药好坏的因素及提高眼用制剂作用效率的方法.结果 眼部给药存在给药屏障,药物可分别经角膜途径和结膜途径发挥局部治疗作用和全身治疗作用.生理因素、药物理化性质及剂型因素均会对药物在眼部传递产生影响.结论 通过加入渗透促进剂、改变药物的剂型及减少给药体积可有效提高眼用制剂作用效率.     

我国抗生素新型给药系统的研究进展

本文主要从不同的给药途径对我国抗生素新型给药系统的研究进展进行了综述.     

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.     

Liposomal ophthalmic drug delivery system I. Triamcinolone acetonide

The potential of liposomes as an ophthalmic drug delivery system was investigated in the rabbit. Triamcinolone acetonide as a model compound for lipophilic drugs was encapsulated into large multilamellar vesicles and instilled into the eye. A suspension form served as a control preparation. Drug distribution was determined at various time intervals. Compared to the suspension, the liposomal form produced significantly higher drug levels in the ocular tissues up to 5 h after the drug administration. The results suggest that liposomal encapsulation of the drug may be a superior drug delivery system for ocular therapy.     

苄达赖氨酴眼用温敏凝胶的制备

目的 制备苄达赖氨酸眼用温敏凝胶并考察其性能.方法 采用冷溶法制备温敏凝胶;试管倒转法考察凝胶浓度、药物含量对相转变温度的影响;无膜溶出法模拟眼部生理环境,考察凝胶的体外溶蚀和药物释放行为.结果 转变温度随凝胶溶液浓度而发生变化;含药量对相变温度无影响;优化处方为泊洛沙姆407浓度17.33%、药物的含量为1 mg·m...     

A two-component drug delivery system using Her-2-targeting thermosensitive liposomes

We report on a new method for enhancing the specificity of drug delivery for tumor cells, using thermosensitive immunoliposomes. The liposomes are conjugated to the antibody trastuzumab (Herceptin^®), which targets the human epidermal growth factor receptor 2 (Her-2), a cell membrane receptor overexpressed in many human cancers. Being thermosensitive, the liposomes only release their contents when heated slightly above body temperature, allowing for the possibility of tissue targeting through localized hyperthermia. Using self-quenching calcein, we demonstrate the release of liposome contents into cell endosomes after brief heating to 42°C. To further increase targeting specificity, we incorporate the concept of a two-component delivery system that requires the interaction of two different liposomes within the same endosome for cytoplasmic delivery. Experimental evaluation of the technique using fluorescently labeled liposomes shows that a two-component delivery system, combined with intracellular disruption of liposomes by hyperthermia, significantly increases specificity for Her-2-overexpressing tumor cells.     

Nanosuspension as an ophthalmic delivery system for certain glucocorticoid drugs

Poorly-water-soluble compounds are difficult to develop as drug products using conventional formulation techniques. The use of nanotechnology to formulate poorly-water-soluble drugs as nanosuspensions offers the opportunity to address many of the deficiencies associated with this class of molecules. In the present study, the high pressure homogenization method used to prepare nanosuspensions of three practically insoluble glucocorticoid drugs; hydrocortisone, prednisolone and dexamethasone. The effect of particle size in the micron and nano-size ranges as well as the effect of viscosity of the nanosuspension on the ocular bioavailability was studied by measuring the intraocular pressure of normotensive Albino rabbits using shiØetz tonometer. The results show that compared to solution and micro-crystalline suspensions it is a common feature of the three drugs that the nanosuspensions always enhance the rate and extent of ophthalmic drug absorption as well as the intensity of drug action. In the majority of cases nanosuspensions extend the duration of drug effect to a significant extent. The data presented confirms that nanosuspensions differ from micro-crystalline suspensions and solution as ophthalmic drug delivery systems and that the differences are statistically, highly to very highly significant. The results confirm also the importance of viscosity of nanosuspension especially in increasing the duration of drug action.     

Liposomal ophthalmic drug delivery system. II. Dihydrostreptomycin sulfate

The carrier ability of liposomes for a model hydrophilic compound vas investigated in the rabbit eye. Dihydrostreptomycin sulfate was encapsulated in various types of liposomes, i.e. large and small uni- and multilamellar vesicles having either positive or neutral surface charge. An aqueous solution served as control preparation. Results indicated that liposomal encapsulation reduced the ocular drug con- centration. Addition of empty liposomes to the control solution did not alter drug levels in most of the ocular tissues. Among the liposomal preparations the large multi- and unilamellar vesicles provided higher drug concentration in all ocular tissue than the small unilamellar ones. Introduction of a positive charge on liposome surface enhanced liposome-conjunctiva interactions. The results suggest that liposomal encapsulation alters drug disposition in the eye lepending on the type of liposomes and the physicochemical properties of the encapsulated drug. In the case of the dihydrostreptomycin sulfate and possibly other hydrophilic drugs the liposomal encapsulation provides no advantages as far as drug delivery is concerned.