Preparation and Characterization of Microcapsules Based on Biodegradable Polymers: Pectin/Casein Complex for Controlled Drug Release Systems

Controlled release of drugs is an important strategy to diminish the drug dose and adverse side effects. Aqueous mixtures of polysaccharides and proteins are usually unstable above a certain biopolymer concentration and phase separation occurs either because of repulsive (segregative) or attractive (associative) interactions. Herein, pectin/casein microcapsules were prepared by complex coacervation aiming at prolonged drug release. The morphological characteristics, particle size, distribution, and release kinetics of microcapsules were studied using as a model the hydrophilic drug acetaminophen. It was detected that complexation of pectin/casein particles occurs at pH values lower than 6, resulting in the formation of spherical particles after spray drying. Microcapsules had a mean diameter of 3.138 and 4.929 μm without drug, and of 4.680 and 5.182 μm with drug using USP and 8003 pectin, respectively. The in vitro release of acetaminophen from microcapsules was slow and the drug release mechanism was controlled by diffusion following first-order kinetics. There was greater release of acetaminophen in simulated gastric fluid than simulated intestinal fluid conditions. Concluding, the polymeric system present herein seemed to be appropriate for a prolonged release of acetaminophen throughout the gastrointestinal tract. Nevertheless, it is likely that it is a promising pectin/casein complex for lipossoluble drugs, which merits further investigation.KEY WORDS: casein, complex coacervation, microcapsules, pectin, release kinetics     

舒芬太尼联合罗哌卡因硬膜外自控镇痛对剖宫产术后应激激素和胃肠动力状态的影响

目的:探讨舒芬太尼联合罗哌卡因硬膜外自控镇痛(PCEA)对剖宫产术后应激激素和胃肠动力状态的影响。方法:选择2017年10月～2018年10月于我院择期行剖宫产术的114例孕产妇为研究对象,所有孕产妇按随机数字表法分为对照组(n=51)和研究组(n=63)。对照组术后予以舒芬太尼联合左旋布比卡因PCEA,研究组术后予以舒芬太尼联合罗哌卡因PCEA。比较两组术后24 h PCA按压次数、镇痛液用量、视觉模拟评分(VAS)、手术前后应激激素、胃肠激素、胃电参数、泌乳素(PRL)水平的变化和不良反应的发生情况。结果:研究组术后24 h PCA按压次数、镇痛液用量、VAS均显著低于对照组(P0.05)。术后24 h,两组血管紧张素Ⅱ(AngⅡ)、去甲肾上腺素(NE)、皮质醇(Cor)、胆囊收缩素(CCK)、血管活性肽(VIP)均较术前显著上升,两组胃动素(MTL)、胃电主功率、胃电频率、正常慢波节律比均较术前明显下降,且研究组以上指标变化幅度均明显小于对照组(P0.05)。研究组术后PRL水平显著高于对照组(P0.05)。两组总不良反应发生率比较差异无统计学意义(P0.05)。结论:舒芬太尼联合罗哌卡因硬膜外自控镇痛可有效减轻剖宫产术后疼痛,抑制应激激素的分泌,改善胃肠动力状态。     

依托咪酯靶控输注联合右美托咪定对胃癌根治术患者应激反应、炎症因子和细胞免疫功能的影响

摘要 目的：观察胃癌根治术患者在依托咪酯靶控输注联合右美托咪定麻醉下,机体细胞免疫功能、炎症因子、应激反应的影响。方法：选取2021年4月~2022年6月期间我院收治的择期行胃癌根治术患者100例,按照信封抽签的形式将患者分为对照组（n=50）和观察组（n=50）,对照组患者麻醉选用依托咪酯注射液靶控输注,观察组则在对照组的基础上结合静脉输注盐酸右美托咪定注射液。观察两组患者不良反应发生情况、血流动力学指标[心率（HR）、收缩压（SBP）、舒张压（DBP）]、应激反应指标[皮质醇（Cor）、肾上腺素（E）、促肾上腺皮质激素（ACTH）]、炎症因子[肿瘤坏死因子-α（TNF-α）、白介素-6（IL-6）、超敏C反应蛋白（hs-CRP）]、细胞免疫功能指标。结果：观察组用药时、拔管时SBP、HR、DBP低于对照组（P<0.05）。两组不良反应发生率组间对比无差异（P>0.05）。观察组术后1 d E、IL-6、Cor、TNF-α、ACTH、 hs-CRP、 CD8⁺低于对照组（P<0.05）。观察组术后1 d CD4⁺、CD3⁺、CD4⁺/CD8⁺高于对照组（P<0.05）。结论：胃癌根治术患者使用依托咪酯靶控输注联合右美托咪定麻醉,血流动力学、应激反应可得到有效控制,炎症因子、免疫功能的影响也可大大减轻,利于手术的顺利进行。     

An Approach for Incorporating Information on Chemical Availability in Soils into Risk Assessment and Risk-Based Decision Making,Prepared by: The New England Environmentally Acceptable Endpoints Workgroup

A regional workgroup comprised of individuals from regulatory agencies, uni versities, and consulting companies was formed to develop an approach for incor porating information on chemical availability in soils into risk assessment and risk based decision making. The approach consists of the following decision framework for including information on chemical availability: (1) Determine the usefulness of incorporating information on bioavailability; (2) Identify information needs from a conceptual model of exposure for the site and from exposure pathways judged critical to the assessment; (3) Identify soil factors that affect bioavailability; (4) Determine the type or form of information (measures and/or models) that can be used within the risk assessment and risk management process; (5) Select methods (measures and/or models) based on the “weight of evidence” or strength of the bioavailability information they will provide and how that information will be used for risk assessment and risk based decision making; (6) Incorporate information into the risk assessment and risk based decision making. These fac tors can be integrated into existing risk based approaches for site management such as Superfund, state approaches, and the ASTM Risk Based Corrective Action Process (RBCA). Consistent with risk assessment guidance, an assessment of chemical availability in soils must consider current as well as reasonably foresee able conditions. The approach recognizes that information on chemical availabil ity is contextual and depends on the receptor and pathway. Further, the value of information depends on how well it is accepted and/or validated for use in regulatory decision making. The workgroup identified four principles for select ing methods (measures and/or models) for obtaining information on chemical availability and for evaluating information on chemical availability for use in risk assessments: (1) soil chemical relevance, (2) pathway relevance, (3) receptor relevance, and (4) acceptance of the method.     

An efficient and selective method for preparing glycosyl sulfoxides by oxidizing glycosyl sulfides with OXONE or t-BuOOH on SiO2

Silica gel adsorbed with OXONE or t-BuOOH was used as a mild oxidant to selectively oxidize glycosyl sulfides to corresponding sulfoxides in good yields and without sulfones formation. This method was also found compatible with various other functional groups in the glycosides.