Nanostructured microspheres produced by supercritical fluid extraction of emulsions

The system poly(lactic-co-glycolic) acid/ piroxicam (PLGA/PX) was selected, as a model system, to evaluate the effectiveness of supercritical carbon dioxide (SC-CO(2)) extraction of the oily phase (ethyl acetate) from oil-in-water emulsions used in the production of polymer/drug microspheres for sustained drug release applications. The influence of process parameters like operating pressure and temperature, flow rate and contacting time between the emulsion and SC-CO(2) was studied with respect to the microsphere size, distribution and solvent residue. Different polymer concentrations in the oily phase were also tested in emulsions formulation to monitor their effects on droplets and microspheres size distribution at fixed mixing conditions. Spherical PLGA microspheres loaded with PX (10% w/w) with mean sizes ranging between 1 and 3 microm and very narrow size distributions were obtained due to the short supercritical processing time (30 min) that prevents the aggregation phenomena typically occurring during conventional solvent evaporation process. A solvent residue smaller than 40 ppm was also obtained at optimized operating conditions. DSC and SEM-EDX analyses confirmed that the produced microparticles are formed by a solid solution of PLGA and PX and that the drug is entrapped in an amorphous state into the polymeric matrix with an encapsulation efficiency in the range of 90-95%. Drug release rate studies showed very uniform drug concentration profiles, without any burst effect, confirming a good dispersion of the drug into the polymer particles.     

Encapsulation of Lipophilic Bioactive Molecules by Microchannel Emulsification

Currently, much effort is being invested in novel formulations of bioactive molecules, such as emulsions, for pharmaceutical, food, and cosmetic applications. Therefore, methods to produce emulsions with controlled-size droplets of uniform size distribution have been developed. On this concern, a microfluidic device called the microchannel (MC) was used in this work for emulsification. This is a novel method for producing monodispersed emulsion droplets with very narrow droplet size distribution and low energy input, due to the spontaneous droplet generation basically driven by the interfacial tension, unlike other conventional emulsification processes. This technology provides the formulation of oil-in-water (O/W) emulsions containing lipophilic active molecules with increased bioavailability, which may be readily absorbed by the human body. MC emulsification enables the preparation of highly monodispersed O/W emulsions, which may be applied as enhancer on active molecules delivery systems, as well as in foodstuff. In this study, formulations of O/W emulsions loaded with bioactive molecules, such as β-carotene and γ-oryzanol, were prepared by the MC emulsification process. Refined soybean oil containing the dissolved lipophilic molecule and either sugar ester or gelatin solution (1 wt.%) were used as the dispersed and continuous phases, respectively. The emulsification process conducted using the asymmetric straight-through MC plate enabled the production of monodispersed O/W emulsions, resulting in β-carotene-loaded O/W emulsions with average droplet size (d _av) of 27.6 μm and coefficient of variation (CV) of 2.3% and γ-oryzanol-loaded droplets with d _av of 28.8 μm and CV of 3.8%. The highly monodisperse β-carotene-loaded droplets were physically stable throughout the storage period observed, resulting in droplets with d _av 28.2 μm and CV of 2.9% after 4 months storage in darkness at 5 °C. Single micrometer-sized monodisperse emulsions loaded with β-carotene were successfully formulated using the grooved MC emulsification, resulting in droplets with d _av of 9.1 μm and CV of 6.2%. This work was funded by The Ministry of Agriculture, Forestry and Fisheries of Japan, through the Food Nanotechnology Project, and the Japan Society for the Promotion of Science.     

Permeation Studies of Indomethacin from Different Emulsions for Nasal Delivery and Their Possible Anti-Inflammatory Effects

The purpose of this research was to develop an emulsion formulation of indomethacin (IND) suitable for nasal delivery. IND was incorporated into the oil phases of oil in water (O/W) and water in oil (W/O) emulsions. For this purpose, different emulsifying agents (Tween 80, Span 80 and Brij 58) were used in two emulsion formulations. When the effects of several synthetic membranes (nylon, cellulose, cellulose nitrate) were compared with the sheep nasal mucosa, the cellulose membrane and sheep nasal mucosa showed similar permeation properties for O/W emulsion (P > 0.05). To examine the absorption characteristics of IND, the anti-inflammatory properties of intravenous solution of IND, intranasal O/W emulsions of IND (with or without enhancers) and intranasal solution of IND (IND-Sol) were investigated in rats with carrageenan-induced paw edema. When citric acid was added to the nasal emulsion, the anti-inflammatory activity was similar to that of intravenous solution (P > 0.05). Finally, it was concluded that, intranasal administration of IND emulsion with citric acid may be considered as an alternative to intravenous and per oral administrations of IND to overcome their adverse effects.     

A novel surfactant nanoemulsion with a unique non-irritant topical antimicrobial activity against bacteria, enveloped viruses and fungi

A novel non-ionic surfactant nanoemulsion designated 8N8 has been tested for its biocidal activity. One percent 8N8 produced effective bactericidal activity against Bacillus cereus, Bacillus subtilis, Haemophilus influenzae, Neisseria gonorrhoeae, Streptococcus pneumoniae, and Vibrio cholerae in 15 minutes. In contrast, most enteric gram-negative bacteria were resistant to 8N8. One percent 8N8 was also virucidal within 15 minutes for all tested enveloped viruses, including Herpes simplex type 1, influenza A and vaccinia viruses. One percent 8N8 also demonstrated fungistatic activity on Candida albicans. The rapid and non-specific inactivation of vegetative bacteria and enveloped viruses, in addition to its fungistatic activity and low toxicity in experimental animals, makes 8N8 a potential candidate for use as a topical biocidal agent.     

醇微乳液中糖化酶性质的研究

糖化酶在正十二醇中稳定性较高;其在由正十二醇／十六烷基三甲基溴化铵／水组成的微乳液中,催化反应的最适温度和ｐＨ值比在水溶液中低;反应的最大速度Ｖ和米氏常数Ｋｍ比其在水溶液中分别提高了４倍和１．５倍;催化低聚糖合成得率有很大提高。     

Recent advances in formulation and application of entomopathogenic fungi for biocontrol of stored-grain insects

The recent advances in biocontrol of stored-grain insects using formulated and unformulated strains of entomopathogenic fungi (EPF) are reviewed and discussed. Several liquid and dry formulations of EPF strains were developed and used against these insects. However, a literature search revealed lack of any commercially registered product of these formulations. Therefore, in order to achieve an effective control of these insects, the following potential areas of future research have been identified and discussed: (i) screening for new effective strains of EPF, in addition to new effective formulations, (ii) applying the most effective strains and formulations selected in the previous step under storage conditions, (iii) optimising the proportions of ingredients in the selected formulations and (iv) integrating the products of the most effective formulations, after registration and commercialisation, in the integrated pest management programmes of stored-grain insects. Such products would constitute an appropriate alternative control means to synthetic insecticides and fumigants commonly used for control of these insects. The various obstacles pertaining to how the selected EPF products are planned to be used in ‘real world’ in stored-grain protection are also critically discussed.     

肠内营养乳剂早期应用对重症脑血管病患者营养支持及感染防治的临床价值研究

摘要 目的：研究肠内营养乳剂（EN）早期应用对重症脑血管病患者营养支持及感染防治的临床价值。方法：按照随机数字表法,将我院2016年1月至2021年1月期间收治的重症脑血管病患者392例分为对照组（n=196）和试验组（n=196）。对照组于患者发病24小时后进行EN支持治疗,试验组在患者发病24小时内给予EN支持治疗。对比两组营养状况、免疫功能、并发症发生率、病情状况和生活自理能力情况。结果：治疗后,试验组白蛋白、前白蛋白、血红蛋白高于对照组（P<0.05）。治疗后,试验组CD3⁺、CD4⁺、CD4⁺/CD8⁺高于对照组,CD8⁺低于对照组（P<0.05）。试验组的生存率则高于对照组,并发症发生率低于对照组（P<0.05）。治疗后,两组日常生活能力日常生活能力量表（ADL）评分较治疗前升高,美国国立卫生院神经功能缺损评分（NIHSS）评分较治疗前下降,且试验组变化程度大于对照组（P<0.05）。结论：EN早期应用有助于改善重症脑血管病患者营养状况,提高其免疫力,降低并发症发生率,改善日常生活活动能力,提高生存率。     

Industrial separation of carboxylic and amino acids by liquid membranes: applicability, process considerations, and potential advantage

Liquid-liquid extraction and membrane separation are well-known separation method of extensive industrial application. Their incorporation into liquid membranes has the potential of several advantages, some of which are of particular interest for the recovery of carboxylic and amino acids: selectivities higher than those attainable by current separation methods, saving on energy costs for final concentration of separated products, high fluxes, compact installation, and low capital and operation costs. Stability of the liquid advantages, can be secured by utilizing extractant blocking polymeric membranes, Applicability, process consideration, and economic implications for recovery for carboxylic and amino acids by various extractant/membrane combinations are discussed. (c) 1993 John Wiley & Sons, Inc.     

Lipase immobilized on hydrophobic porous polymer supports prepared by concentrated emulsion polymerization and their activity in the hydrolysis of triacylglycerides

Microporous polymer supports for the immobilization of lipase have been prepared by the polymerization of a concentrated emulsion precursor. The concentrated emulsion consists of a mixture of styrene and divinyl-benzene containing a suitable surfactant and an initiator as the continuous phase and water as the dispersed phase. The volume fraction of the latter phase was greater than 0.74, which is the volume fraction of the dispersed phase for the most compact arrangement of spheres of equal radius. The lipase from Candida rugosa has been immobilized on the internal surface of the hydrophobic microporous poly(styrene-divinyl benzene) supports and used as biocatalysts for the hydrolysis of triacylglycerides. The effects of the amount of surfactant, of the molar ratio of divinylbenzene/styrene in the continuous phase, and of the aquaphilicity of the supports on the adsorption, activity, and stability of the immobilized lipase have been investigated. The microporous poly(styrene-divinylbenzene) adsorbents constitute excellent supports for lipase because both the amount adsorbed is large and the rate of enzymatic reaction per molecule of lipase is higher for the immobilized enzyme than for the free one. (c) 1993 John Wiley & Sons, Inc.     

改善蛋白质药物PELA控释微球释放性能的研究

开展了以乙酸乙酯(EA)与二氯甲烷(MC)的混合溶液为有机溶剂、以单甲氧基聚乙二醇-聚-DL-乳酸(PELA)为膜材的W／O／W复乳-分步固化法制备蛋白质药物控释微球的研究。为解决微球突释率高、且突释后的释药速度缓慢的问题,实现后期快速释放,以溶菌酶为模型蛋白,重点考察了膜材组成、内水相体积以及外水相盐浓度对微球释药速率的影响。结果表明,当外水相盐浓度增大至1.5％时可将释放率由22％提升至45％,是一种较好的加快微球释药速率的途径,因此可通过选择适当的外水相盐浓度,达到所期望的药物释药速率。