polymeric support

  • 文章类型: Journal Article
    用于治疗各种眼部疾病的眼科药物通常通过滴眼剂给药。然而,由于解剖和生理因素,活性成分的生物利用度较低。为了将药物在角膜上的停留时间增加到足够的水平,最近已经提出了治疗性隐形眼镜。构成隐形眼镜的聚合物载体装载有药物;以这种方式,对靶器官有直接有效的药理作用,促进活性成分的延长释放。将眼用药物掺入隐形眼镜可以通过不同的技术进行;如今,主要采用浸泡法。为了提高载药隐形眼镜的治疗性能,最近提出了创新的方法,包括超临界二氧化碳的浸渍。对治疗性隐形眼镜生产和应用的最新审查提供了有关最有效制备方法的有用信息,最近的成就和未来的前景。
    Ophthalmic drugs used for the treatment of various ocular diseases are commonly administered by eye drops. However, due to anatomical and physiological factors, there is a low bioavailability of the active principle. In order to increase the drug residence time on the cornea to adequate levels, therapeutic contact lenses have recently been proposed. The polymeric support that constitutes the contact lens is loaded with the drug; in this way, there is a direct and effective pharmacological action on the target organ, promoting a prolonged release of the active principle. The incorporation of ophthalmic drugs into contact lenses can be performed by different techniques; nowadays, the soaking method is mainly employed. To improve the therapeutic performance of drug-loaded contact lenses, innovative methods have recently been proposed, including the impregnation with supercritical carbon dioxide. This updated review of therapeutic contact lenses production and application provides useful information on the most effective preparation methodologies, recent achievements and future perspectives.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    A chitosan membrane composed by 60% (w/w) chitosan and 40% (w/w) Aliquat®336 has been proposed as a new biopolymeric support for electromembrane extraction. The new support has been characterized by Scanning Electron Microscopy, resulting a 30-35 µm thickness. Amoxicillin, nicotinic acid, hippuric acid, salicylic acid, anthranilic acid, ketoprofen, naproxen and ibuprofen have been successfully extracted using the proposed support. Better enrichment factors were obtained for the acidic polar analytes than for the non-steroidal anti-inflammatory compounds (ranging from 118 for hippuric acid and 20 for ibuprofen). Electromembrane extraction was developed applying a DC voltage of 100 V, 1-octanol as supported liquid membrane and 20 min of extraction. The target analytes have also been satisfactorily extracted from human urine samples, providing high extraction efficiencies. The chitosan membrane is presented as a promising alternative for supporting liquid membrane compared to commonly used materials for this purpose.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    Polydibenzo-18-crown-6 was utilized as a co-catalyst and polymeric support in combination with potassium iodide for the synthesis of cyclic carbonates from carbon dioxide and epoxides under mild and solvent-free conditions. The efficiency of this catalytic system can be easily increased by loading the polymer with KI prior to the reaction. The influence of various reaction parameters were studied thoroughly. The scope and limitation of the catalyst system was studied at 80 °C and 100 °C. A large number of terminal epoxides (14) were converted to the desired cyclic carbonates in yields up to 99%. We could successfully recover and reuse the catalyst >20 times with excellent yields up to 99%. Although, we observed that the activity gradually decreased after repetitive cycles. This decrease was attributed to KI leaching and partial degradation caused by mechanical stirring. This assumption is supported by scanning electron microscopy and energy dispersive X-ray spectroscopy.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

公众号