蛋白质的PEG修饰

近年来,聚乙二醇修饰技术已经成为改良蛋白药物最有效的技术之一,蛋白质药物经聚乙二醇修饰后其性质会发生多种变化,该技术也得到了越来越广泛的应用。目前已经有十余种聚乙二醇修饰的蛋白药物上市,在临床疗效和安全方面有优良表现。此文综述了蛋白药物聚乙二醇修饰技术的发展以及修饰对蛋白质性质的影响,聚乙二醇修饰的主要方法,有关的鉴定与检测方法,修饰产品的开发与应用状况,并展望了聚乙二醇修饰技术的发展方向。     

蛋白药物聚乙二醇修饰技术研究进展

近年来,聚乙二醇修饰技术已经成为改良蛋白药物最有效的技术之一,得到越来越广泛的应用。目前已经有十余种聚乙二醇修饰的蛋白药物上市,在临床疗效和安全方面有优良表现。此文综述了蛋白药物聚乙二醇修饰技术的发展,特别是聚乙二醇定点修饰的新技术和新方法,并展望了聚乙二醇修饰技术的发展方向。     

聚乙二醇修饰蛋白药物及其应用

目的介绍聚乙二醇修饰蛋白的研究及应用新进展。方法参阅相关文献,进行整理归纳。结果聚乙二醇修饰蛋白后,稳定性增强,免疫性降低,生物半衰期延长,药物动力学优化。结论本法不仅用途广泛,而且具有较高的实用价值和进一步开发研究的潜力。     

药物聚乙二醇化的研究进展

聚乙二醇化是化学分子变构中重要的技术之一,是药物研究和开发的里程碑。本文介绍了聚乙二醇修饰药物的优化条件以及优化后药物在体内药动学和药效学等性质的改变,举例说明聚乙二醇化技术在蛋白多肽及纳米脂质体等方面的研究应用,并展望聚乙二醇修饰技术在国内外医药领域的应用前景。     

改善蛋白药代动力学的方法——蛋白聚乙二醇化的研究进展

蛋白作为治疗药物有很大的前途。然而，许多蛋白很容易被体内的蛋白酶水解，具有较快的肾脏清除率和体内代谢半衰期短的缺点；同时治疗蛋白是异源物质，易引起机体的免疫排斥反应，从而限制了治疗蛋白的使用范围。聚乙二醇化是聚乙二醇通过某种官能团与蛋白相连的过程，其结果是提高了蛋白的分子量、增强了抗蛋白酶水解的能力、降低了免疫原性和改善了药代动力学参数。本文综述了蛋白与聚乙二醇的连接方法、蛋白聚乙二醇化的分析方法和聚乙二醇化在临床治疗药物中的应用。     

聚乙二醇修饰脂质小分子在胶束给药系统中的研究进展

脂质分子因具有无毒性,无免疫源性以及良好的生物兼容性,广泛应用于药物载体研究中。经聚乙二醇修饰的脂质具有双亲性,在水中可自组装形成胶束。该类聚合物载体能够增强药物的溶解度及稳定性,改善药物在体内的药动学行为,增强疗效等,在纳米给药系统中具有广阔的应用前景。本文综述了在胶束给药系统中应用较多的聚乙二醇化脂质小分子,主要包括聚乙二醇修饰的磷脂,胆固醇,脂肪酸等。     

聚乙二醇化重组蛋白药物生产质量控制的一般考量

聚乙二醇化重组蛋白药物是由聚乙二醇(PEG)对重组蛋白药物修饰而成,在保留原型重组蛋白生物学活性前提下,克服原型蛋白体内代谢快、稳定性差、需多次给药等缺点,但也存在一定的特殊性,在对其质量控制的相关指导原则有限的情况下,通过对其生产用原材料控制、生产过程中工艺控制、中间产品及终产品的质量控制、稳定性研究等方面进行探讨,为其研究开发和生产质量控制提供一定参考。     

聚乙二醇前药设计原理与应用研究进展

聚乙二醇（polyethylene glycol,PEG）目前被广泛应用于肿瘤药物的修饰,当与药物分子偶联时,可以将其优良性质赋予修饰后的药物分子,改变药物的溶解性,在其修饰的药物周围产生空间屏障,减少药物的酶解,避免药物在肾脏的代谢中很快被消除,同时能被动靶向肿瘤细胞,降低药物毒性。聚乙二醇是中性、无毒且具有独特理化性质和良好生物相容性的高分子聚合物,也是经美国食品药物管理局（FDA）批准的极少数能作为体内注射给药的合成聚合物之一,已得到市场的认可。该文综述了近几年聚乙二醇修饰的前药研究进展,且就聚乙二醇修饰的原理、设计、运用及面临的挑战进行了论述。     

蛋白多肽类药物聚乙二醇化修饰研究进展

近年来,越来越多具有生物活性的蛋白多肽类药物被发现,因其生理功能上的高效性及专一性而广泛用于治疗各种疾病。但由于其在体内易被降解,且生物半衰期短,使其应用受到了限制。通过化学修饰的方法,可以延长蛋白肽类药物的生物半衰期,提高药效,降低副作用。聚乙二醇能有效增加蛋白多肽类药物在体内的稳定性,本文就聚乙二醇共价连接修饰蛋白质及多肽类药物做一综述。     

蛋白质药物的聚乙二醇修饰

蛋白质药物经聚乙二醇修饰后其性质会发生多种变化。本文综述了该项技术的国内外研究现状，包括聚乙二醇修饰的原理与方法，修饰对蛋白质性质的影响，修饰方法的生物优化，有关的鉴定与检测方法及修饰产品的开发与临床应用状况。     

Development and in vivo evaluation of an oral insulin-PEG delivery system.

Insulin-monomethoxypoly(ethylene glycol) derivatives were obtained by preparation of mono- and di-terbutyl carbonate insulin derivatives, reaction of available protein amino groups with activated 750 Da PEG and, finally, amino group de-protection. This procedure allowed for obtaining high yield of insulin-1PEG and insulin-2PEG. In vivo studies carried out by subcutaneous injection into diabetic mice demonstrated that the two bioconjugates maintained the native biological activity. In vitro, PEGylation was found to enhance the hormone stability towards proteases. After 1 h incubation with elastase, native insulin, insulin-1PEG and insulin-2PEG undergo about 70, 30 and 10% degradation, respectively, while in the presence of pepsin protein degradation was 100, 70 and 50%, respectively. The attachment of low molecular weight PEG did not significantly (P >0.05) alter insulin permeation behavior across the intestinal mucosa. Insulin-1PEG was formulated into mucoadhesive tablets constituted by the thiolated polymer poly(acrylic acid)-cysteine. The therapeutic agent was sustained released from these tablets within 5 h. In vivo, by oral administration to diabetic mice, the glucose levels were found to decrease of about 40% since the third hour from administration and the biological activity was maintained up to 30 h. According to these results, the combination of PEGylated insulin with a thiolated polymer used as drug carrier matrix might be a promising strategy for oral insulin administration.     

Synthesis and hydrolytic behavior of ibuprofen prodrugs and their PEGylated derivatives

Polyethylene glycol (PEG) derivatives of ibuprofen were prepared by esterification of PEG monosuccinate with hydroxy ethyl ester (HEE), hydroxy ethylamide (HEA), and hydroxy ethyl thioester (HET) of ibuprofen. Hydrolysis of HEE-PEG, HEA-PEG, and HET-PEG were studied in vitro with or without esterases to investigate the applicability of these PEGylated prodrugs. The polymeric prodrugs released major fraction of the parent drug (ibuprofen) and a small fraction of hydroxy ethyl derivatives after 48 hr. In HET-PEG, the amount of drug release was higher than HEE-PEG and HEA-PEG. The difference between acidic and alkali buffered solutions was considerable. In human plasma, 50% of drug was released after 150 hr incubation at 37°C from HET-PEG.     

Synthesis and Hydrolytic Behavior of Ibuprofen Prodrugs and their PEGylated Derivatives

Polyethylene glycol (PEG) derivatives of ibuprofen were prepared by esterification of PEG monosuccinate with hydroxy ethyl ester (HEE), hydroxy ethylamide (HEA), and hydroxy ethyl thioester (HET) of ibuprofen. Hydrolysis of HEE-PEG, HEA-PEG, and HET-PEG were studied in vitro with or without esterases to investigate the applicability of these PEGylated prodrugs. The polymeric prodrugs released major fraction of the parent drug (ibuprofen) and a small fraction of hydroxy ethyl derivatives after 48 hr. In HET-PEG, the amount of drug release was higher than HEE-PEG and HEA-PEG. The difference between acidic and alkali buffered solutions was considerable. In human plasma, 50% of drug was released after 150 hr incubation at 37°C from HET-PEG.     

Comparative assessment of two indices of drug induced permeability changes in the perfused rat intestine

In the present study, two indices of acute intestinal permeability changes were investigated as measurements of drug induced intestinal damage. The first method was based on 14C-polyethylene glycol (PEG) 4000 permeability assessment and the second was based on histological evaluation of the intestine. The test compounds were ibuprofen, ketoprofen and naproxen and the alanine, glycine and phenylalanine amide derivatives of ibuprofen. Perfusion studies were carried out using a rat model. Post-perfusion, the gut was fixed and tissue changes were assessed and scored. Ibuprofen, ketoprofen and naproxen altered the barrier properties of the intestine to PEG 4000 with significantly higher scores (p<0.05) for gastrointestinal toxicity relative to blank buffer. For ketoprofen, PEG 4000 permeability and intestinal damage scores increased with increasing ketoprofen concentration. Ibuprofen amide derivatives did not induce significant histological damage or PEG 4000 permeability when compared with ibuprofen. A correlation coefficient of 0.91 is obtained when intestinal damage scores are plotted against PEG 4000 permeability for all compounds. Both indices are proposed as rapid and useful measures of drug induced acute intestinal damage.     

Implication of inclusion complexation of glimepiride in cyclodextrin-polymer systems on its dissolution, stability and therapeutic efficacy

The effect of complexation of glimepiride, a poorly water-soluble antidiabetic drug, with β-cyclodextrin and its derivatives (HP-β-CyD and SBE-β-CyD) in presence of different concentrations of water-soluble polymers (HPMC, PVP, PEG 4000 and PEG 6000) on the dissolution rate of the drug has been investigated. The results revealed that the dissolution rate of the drug from these ternary systems is highly dependent on polymer type and concentration. The dissolution rate of the drug from ternary systems containing PEG 4000 or PEG 6000 seems to be generally higher than from systems containing HPMC or PVP. An optimum increase in the dissolution rate of the drug was observed at a polymer concentration of 5% for PEG 4000 or PEG 6000 and at 20% concentration of HPMC or PVP. The dissolution rate of the drug from the ternary system glimepiride–HP-β-CyD–5% PEG 4000 was high compared to the other systems. Tablets containing the drug or its equivalent amount of this ternary system were prepared and subjected to accelerated stability testing at 40 °C/75% R.H. to investigate the effect of storage on the chemical stability as well as therapeutic efficacy of the tablets. The results revealed stability of the tablets and consistent therapeutic efficacy on storage.     

修饰脂质体的可断裂聚乙二醇脂质衍生物的研究进展

聚乙二醇脂质衍生物可增加脂质体的稳定性，延长其体内循环时间。传统的长循环材料由于连接聚乙二醇与脂质的化学键太稳定，导致脂质体内容物释放延迟而影响药效。近年来提出可断裂聚乙二醇脂质衍生物的概念，该类衍生物具有可以在人的生理或病理条件下断裂的性质，能够延长脂质体体内循环时间，在到达靶部位后由于聚乙二醇已经从脂质体表面脱落，脂质体可以与病变细胞结合，从而将药物送入细胞。本文综述了可断裂聚乙二醇脂质衍生物的种类、断裂类型、在脂质体中的应用概况及在应用中的优势和局限。     

Delivery of Therapeutic Proteins

The safety and efficacy of protein therapeutics are limited by three interrelated pharmaceutical issues, in vitro and in vivo instability, immunogenicity and shorter half-lives. Novel drug modifications for overcoming these issues are under investigation and include covalent attachment of poly(ethylene glycol) (PEG), polysialic acid, or glycolic acid, as well as developing new formulations containing nanoparticulate or colloidal systems (e.g., liposomes, polymeric microspheres, polymeric nanoparticles). Such strategies have the potential to develop as next generation protein therapeutics. This review includes a general discussion on these delivery approaches.     

聚乙烯亚胺非病毒基因载体结构修饰研究进展

聚乙烯亚胺（PEI）作为最经典的非病毒基因载体之一,由于其高转染效率,在基因递送领域受到极大的关注,但其毒性限制了聚乙烯亚胺的应用。本文综述了对聚乙烯亚胺进行不同的结构修饰,如多糖修饰、PEG修饰和低分子聚乙烯亚胺衍生物等,以实现在不显著降低转染效率的前提下减少细胞毒性。     

PLGA-PEG-PLGA tri-block copolymers as in situ gel-forming peptide delivery system: effect of formulation properties on peptide release

Various controlled peptide and protein delivery systems have been investigated for their potential for treatment of chronic diseases. In situ gelling systems are very attractive due to their biocompatibility, biodegradability, and simple manufacturing processes. The objective of this work was to investigate the effect of different excipients on release profile of calcitonin as a model protein from PLGA-PEG-PLGA thermally reversible gels. PLGA-PEG-PLGA with the ratio of PLGA to PEG equal to 2.5 was synthesized and characterized by (1)H NMR and gel permeation chromatography (GPC). The PLGA-PEG-PLGA polymeric solutions (25% w/w) containing calcitonin (0.05% w/w) and other excipients in various concentrations were prepared, and drug release from the thermally reversible gels was evaluated. It was shown that drug release from the systems was dramatically reduced when PEG 200 or PEG 1000 was added to the systems. This may be due to the effect of PEG as an internal cross-linking agent or the formation of PEG complexes that decrease the rate of drug release. Sodium laurel sulfate (SLS) was also shown to reduce the rate of drug release from the systems. This may be due to the large ionic heads of SLS that attract counterions of calcitonin. It can be concluded that the drug release rate from the systems can be controlled by using different excipients.     

PLGA-PEG-PLGA Tri-Block Copolymers as In Situ Gel-Forming Peptide Delivery System: Effect of Formulation Properties on Peptide Release

Various controlled peptide and protein delivery systems have been investigated for their potential for treatment of chronic diseases. In situ gelling systems are very attractive due to their biocompatibility, biodegradability, and simple manufacturing processes. The objective of this work was to investigate the effect of different excipients on release profile of calcitonin as a model protein from PLGA-PEG-PLGA thermally reversible gels. PLGA-PEG-PLGA with the ratio of PLGA to PEG equal to 2.5 was synthesized and characterized by ¹H NMR and gel permeation chromatography (GPC). The PLGA-PEG-PLGA polymeric solutions (25% w/w) containing calcitonin (0.05% w/w) and other excipients in various concentrations were prepared, and drug release from the thermally reversible gels was evaluated. It was shown that drug release from the systems was dramatically reduced when PEG 200 or PEG 1000 was added to the systems. This may be due to the effect of PEG as an internal cross-linking agent or the formation of PEG complexes that decrease the rate of drug release. Sodium laurel sulfate (SLS) was also shown to reduce the rate of drug release from the systems. This may be due to the large ionic heads of SLS that attract counterions of calcitonin. It can be concluded that the drug release rate from the systems can be controlled by using different excipients.