光诱导非手性聚合物的手性研究进展

手性聚合物在手性识别与传感、手性开关、不对称催化和生物医药领域有着重要作用。圆偏振光作为一种手性物理源,由于来源简单易取,操作方便,已经被用于诱导构建非手性聚合物的手性结构。在已报道的例子中,圆偏振光诱导主链和侧链聚合物的手性机理完全不同。本综述主要讨论了在膜和溶液聚集体状态下,非手性侧链型偶氮聚合物的光诱导超分子手性和主链共轭聚合物的光诱导轴手性,并讨论了圆偏振光的偏振状态和入射光波长对聚合物手性的影响,归纳总结了已取得的研究进展和作用机制,并对圆偏振光的应用发展前景进行了简要概述。     

微球给药系统载体材料的研究进展

微球给药系统具有广阔的开发和应用前景,一直是药剂学研究的热点。通过检索2016年我国学者在国内外期刊上发表的相关论文,从天然高分子材料、合成高分子材料和无机材料3个方面,分类综述了我国在微球给药系统载体材料领域的研究进展,并结合国内外微球产品进行总结分析,为相关研究员提供参考。     

咳喘灵高分子涂膜剂治疗急慢性支气管炎临床观察附:193例病例报告

对中中药配方提取物与高分子材料经相结合精制而成的外用涂敷药物－咳喘灵高分子涂膜剂进行了急慢性支气管炎的初步临床疗效观察,结果表明其具有较好的缓解和治疗急慢性支气管炎的作用,值得进一步研究。     

蔗糖基聚合物作为缓释片剂载体的应用研究

目的:研究蔗糖基聚合物作为缓释片的载体的可行性.方法:以不同相对分子质量的蔗糖基聚合物为载体制备非诺络芬钙的缓释片,于1～12 h定时地以紫外分光光度法测定缓释片在人工肠液中的释放度,绘制释放度随时间变化的释放曲线.结果:12 h内非诺络芬钙在人工肠液中能够平稳地缓慢释放,蔗糖基聚合物的相对分子质量越大,释放速率越慢.结论:蔗糖基聚合物可以作为缓释片的载体,其中以MW=79.4K的缓释效果最佳.     

形状记忆输卵管避孕材料的急性毒性研究

目的 探明形状记忆输卵管避孕材料的急性毒性,为临床的安全使用提供依据和资料.方法 形状记忆输卵管避孕材料浸提液腹腔注射给药,以最大允许给药剂量为最高剂量,观察小鼠的死亡率和脏器的感官病理改变.连续观察14d.结果 给药后,各种剂量下均未见中毒症状,动物活动自如,皮毛光滑,未出现死亡.存活动物体质量无明显变化;肉眼未见脏器明显的病理改变.结论 形状记忆输卵管避孕材料急性单次接触条件下的生物安全性良好.     

Preparation and characterization of Antheraea assama silk fibroin based novel non‐woven scaffold for tissue engineering applications

The quest for novel materials as scaffolds with suitable micro‐architecture for supporting tissue neogenesis in tissue engineering and regenerative medicine (TERM) is continuing. In this paper we report an Antheraea assama silk‐based non‐woven fibroin scaffold for applications in TERM. The novel three‐dimensional scaffold is highly interconnected and porous, with a pore size of 150 µm, porosity of 90% and water uptake capacity of 85%. FTIR revealed a typical β‐sheet structure of fibroin. The scaffold has thermal and mechanical properties superior to those of Bombyx mori, as revealed by DSC, TGA and tensile tests. The scaffold exhibited satisfactory blood compatibility, as determined by thrombogenicity, haemolysis, platelet/leukocyte count, platelet adhesion and protein adsorption studies. The scaffold was found to be cytocompatible with human cell lines A549, KB, HepG2 and HeLa for a period of up to 4 weeks. SEM analysis revealed excellent attachment, spreading and migration of cells in the scaffold. MTT assay was performed to estimate the viability and growth of cells in the matrix. Quantification of collagen in cell–scaffold constructs was done by picro‐Sirius red assay. Ex ovo chorioallantoic membrane assay and nitric oxide estimations in spent culture medium showed the scaffold's ability to promote angiogenesis. Finally, the biodegradability of the scaffold was determined by the weight loss observed upon treatment with trypsin over a period of 4 weeks. The results reveal that the fibroin from A. assama is a promising candidate as a biocompatible, biomimetic and biodegradable biomaterial of natural origin for applications in TERM. Copyright © 2009 John Wiley & Sons, Ltd.     

双配体修饰聚合物泡囊的制备及细胞摄取

目的构建一种主动靶向的新型纳米药物载体——聚合物泡囊(polymer vesicles,PVs),并考察其细胞摄取。方法以马来酰亚胺-聚乙二醇-聚乳酸-羟基乙酸共聚物(MAL-PEG-PLGA)为载体材料,通过自组装制备PVs,用转铁蛋白(Tf)与Tet-1对PVs进行修饰,构建纳米药物载体(Tf/Tet-1-PVs)。以香豆素-6作为荧光探针包载于药物载体,考察脑微血管内皮细胞(BCEC)及神经细胞(Neuro-2a)对载体系统的摄取。结果 PVs粒径约80nm,形态圆整,电镜观察具有明显膜层结构。BCEC细胞和Neuro-2a细胞对Tf/Tet-1-PVs的摄取均显著优于空白对照组和单配体修饰对照组。结论 PVs经双配体Tf及Tet-1修饰后可促进脑微血管内皮细胞和神经细胞的摄取。     

Role of polymer–drug conjugates in organ-specific delivery systems

Polymers have been utilized to deliver the drug to targeted site in controlled manner, achieving the high-therapeutic efficacy. Polymeric drug conjugates having variable ligands as attachments have been proved to be biodegradable, stimuli sensitive and targeted systems. Numerous polymeric drug conjugates having linkers degraded by acidity or intracellular enzymes or sensitive to over expressed groups of diseased organ/tissue have been synthesized during last decade to develop targeted delivery systems. Most of these organs have number of receptors attached with different cells such as Kupffer cells of liver have mannose-binding receptors while hepatocytes have asialoglycoprotein receptors on their surface which mainly bind with the galactose derivatives. Such ligands can be used for achieving high targeting and intracellular delivery of the drug. This review presents detailed aspects of receptors found in different cells of specific organ and ligands with binding efficiency to these specific receptors. This review highlights the need of further studies on organ-specific polymer–drug conjugates by providing detailed account of polymeric conjugates synthesized till date having organ-specific targeting.     

Engineering of polymer–surfactant nanoparticles of doxycycline hydrochloride for ocular drug delivery

Abstract

Context: Physiologic barriers of the eye, short precorneal drug residence time and poor corneal penetration are the few reasons for reduced ocular bioavailability.

Objective: This study was aimed to develop novel polymer–surfactant nanoparticles of hydrophilic drug doxycycline hydrochloride (DXY) to improve precorneal residence time and drug penetration.

Materials and methods: Nanoparticles were formulated using emulsion cross-linking method and the formulation was optimized using factorial design. The prepared formulation was characterized for particle size, ζ potential, encapsulation efficiency, in vitro drug release and ex vivo drug diffusion studies. The antibacterial activity studies were also carried out against Escherichia coli and Staphylococcus aureus using the cup-plate method. In vivo eye irritation study was carried out by a modified Draize test in rabbits.

Results and discussion: The particle size was found to be in the range of 331–850?nm. About 45–80% of the drug was found to be encapsulated in the nanoparticles. In vitro release demonstrated sustained release profile. Lower flux values in case of nanoparticles as compared to DXY pure drug solution in ex vivo diffusion studies confirmed the sustained release. The nanoparticles were found to be significantly effective (p?<?0.001) than DXY aqueous solution due to sustained release of doxycycline from nanoparticles in both the E. coli and S. aureus strains. The formulation was found to be stable over entire stability period.

Conclusion: The developed formulation is safe and suitable for sustained ocular drug delivery.     

Synthesis of Telechelic and Three‐Arm Polytetrahydrofuran‐block‐amylose

Telechelic amine terminated polytetrahydrofuran (PTHF) is prepared via cationic ring opening polymerization (CROP) of THF, initiated by trifluoromethanesulphonic anhydride (triflic anhydride). Hexamethylene tetramine (HMTA) is used as a terminating agent. The resulting HMTA terminated PTHF is hydrolyzed to result in an amine terminated PTHF. Reductive amination is carried out by reacting the PTHF with maltoheptaose resulting in maltoheptaose‐b‐PTHF‐b‐maltoheptaose. The product is prepared as a primer for the enzymatic polymerization to synthesize amylose‐b‐PTHF‐b‐amylose. In addition, a three‐arm PTHF is prepared via CROP of THF. The initiator is synthesized in situ by the reaction of triflic anhydride and triethanol amine. The resulting amine terminated three‐arm PTHF is reacted with maltoheptaose to synthesize a three‐arm PTHF‐b‐maltoheptaose which can be used for the enzymatic synthesis of three‐arm PTHF‐b‐amylose. Characterization of the products is difficult due to the amphiphilic behavior of both telechelic amylose‐b‐PTHF‐b‐amylose and three‐arm PTHF‐b‐amylose. Therefore, the analysis of the products is mainly based on attenuated total reflectance Fourier transform infrared spectroscopy.