超临界流体色谱仪在天然产物研究中的应用

超临界流体可以用作色谱的流动相,使混合物质在色谱柱上得到分离,这种分离方法被称为超临界流体色谱(supercritical fluid chromatography,SFC).作为色谱流动相的超临界流体,其作用与超临界流体萃取(supercritical fluid extraction,SFE)类似.超临界流体对物质的溶解能力比一般气体大的多,相当于有机溶剂,但比有机溶剂的扩散速度快、黏度低、表面张力小.超临界流体溶解能力的大小随其压力的变化而改变.由于超临界流体的黏度很低,SFC就可采用比高效液相色谱(HPLC)高的流速,因此具有分析/制备快的优点.     

超临界流体萃取技术及其在中药提取中的应用

超临界流体萃取技术在中药分离、精制领域有着重要的作用,目前已初步形成一个新的产业.介绍了超临界流体的萃取原理,超临界流体的种类,影响超临界流体萃取的主要因素,以及该技术在挥发油类、生物碱类、黄酮类、醌类、香豆素与木脂素类、皂苷类中药提取物中的应用.     

超临界流体技术在生物工程领域的研究进展

目的介绍超临界流体技术在生物工程领域的应用和发展。方法检索归纳近年来国内外超临界技术与生物工程技术结合应用的29篇相关文献资料。结果已在生物工程领域应用的超临界流体技术有超临界流体酶催化、超临界流体发酵、超临界流体灭菌和细胞破碎技术等。结论超临界流体技术在生物工程领域的应用大有潜力。     

超临界流体萃取技术在中药生物碱提取中的应用

目的对超临界二氧化碳流体萃取中药中生物碱的应用进行综述。方法通过与传统的生物碱提取方法相比较 ,总结了超临界二氧化碳流体萃取生物碱的工艺特点及应用。结果与结论超临界流体萃取技术可以有效地提取中药中的生物碱 ,并具有产率高、方便快捷、后处理简单、无污染等优点     

超临界CO2流体萃取丹参素的工艺研究

目的研究萃取丹参素的最佳工艺条件。方法通过正交设计,用超临界CO2流体萃取,优化出合理工艺条件,并与传统溶剂提取工艺相对照。结果超临界CO2流体萃取率为传统工艺萃取率的1．1倍。结论超临界CO2流体萃取丹参素具有开发价值。     

超临界流体制备纳米药物的研究进展

目的对目前应用超临界流体制备纳米药物的方法进行综述。方法参考近年来国内外文献共25篇,以药物在超临界流体中的溶解度为依据,对其制备方法进行分类并评论。结果超临界流体具有溶解性好、传质能力高及渗透性强等优点,且在临界点附近,温度和压力的微小改变就会引发药物溶解度的巨大变化;CO2是最为常用的超临界流体。根据药物在超临界流体中的溶解性,纳米药物制备方法可以分为溶剂法和反溶剂法,其经典技术分别为超临界流体快速膨胀技术的和超临界流体反溶剂技术,这两种经典技术均存在粒子聚集的缺点,但固体潜溶剂超临界流体快速膨胀技术、超临界流体膨胀至水溶液技术和提高传质超临界流体反溶剂技术三种新技术均可克服这一缺点,且所制备的纳米药物粒径更小、更为均匀。结论作为一种新兴的纳米药物制备技术,超临界流体技术具有高效节能、绿色环保等优点,极具发展前景和实际应用价值。     

超临界流体技术制备微细颗粒的方法及装置

综述三种重要的超临界流体技术制备微细颗粒的方法:超临界流体快速膨胀法、超临界流体抗溶剂法及气体饱和溶液沉析法,对这三种颗粒制备方法的工艺原理、装置及其各自的特点进行了比较,并对超临界流体技术制备微细颗粒中存在的问题和发展前景进行了分析和展望。     

超临界流体萃取技术及其在生物样本萃取中的应用

对超临界流体的性质、超临界流体萃取技术的特点及其在生物样本萃取中应用实例进行了介绍。超临界流体萃取技术是新近发展迅速并在生物样本萃取中具有独特优势的一门技术。     

胡桃楸树皮及其果皮超临界CO_2萃取物的GC-MS分析

目的分析胡桃楸树皮超临界CO2流体萃取成分,并与果皮相比较。方法超临界CO2流体萃取胡桃楸树皮与果皮,GC-MS技术分析两种萃取物的化学成分。结果从胡桃楸树皮与果皮中分别鉴定出28种和34种化学成分,其中有13种为二者共有成分(主要为烃类和有机酸)。结论胡桃楸树皮与果皮超临界CO2流体萃取物有相同成分,但不同的成分较多。     

超临界流体沉积技术在药剂学中的应用

目的：综述近年来超临界流体沉积技术在药剂学中的研究进展，特别是在给药系统方面的应用特点，为国内药剂学利用超临界流体技术的研究提供参考。方法：根据国内外文献，较全面地介绍了超临界流体的特征、溶解性质、超临界流体沉积技术及其在药剂学中的应用，特别是国外的研究情况。结果与结论：超临界流体技术在药剂学领域有较好的应用前景。     

Ampicillin micronization by supercritical assisted atomization

The micronization technique called supercritical assisted atomization (SAA) was used to produce ampicillin microparticles with controlled particle size and particle size distribution suitable for aerosol drug delivery. The process is based on the solubilization of supercritical CO2 in a liquid solution. The ternary mixture is then sprayed through a nozzle and, as a consequence of enhanced atomization, solid microparticles are formed. Water and organic solvents were tested with ampicillin to determine the influence of the solvent on the process mechanism. SAA process parameters were studied by testing different supercritical/liquid solvent flow ratios, ampicillin concentrations in the liquid solution and nozzle diameters. The effect of these parameters on morphology, particle size and particle size distribution of microparticles was analysed. Ampicillin particles suitable for aerosol delivery in the size range 1-5 microm were obtained using buffered water. Moreover, by varying the solute concentration, ampicillin particles in a narrower range (1-3 microm) than that usually suggested for aerosol deliverable drugs were obtained. This is an example of particle size tailoring by SAA.     

Corticosteroid microparticles produced by supercritical-assisted atomization: process optimization, product characterization, and "in vitro" performance

In this work, the production of dexametasone and dexametasone acetate microparticles is proposed using supercritical-assisted atomization (SAA). This process is based on the solubilization of supercritical carbon dioxide in a liquid solution containing the drug; then, the ternary mixture is sprayed through a nozzle and submicroparticles are formed as a consequence of the enhanced atomization. Several process parameters such as different organic solvent (methanol and acetone), solute concentration and flow rate ratio between the liquid solution and carbon dioxide are investigated; their influence is evaluated on the morphology and size of precipitated particles. Spherical corticosteroid particles with mean diameters ranging from 0.5 to 1.2 microm are produced at the optimum operating conditions and narrow particle size distributions (PSDs) have also been obtained. No drug degradation was observed after SAA processing and solvent residues of 300 and 500 ppm for acetone and methanol, respectively, were measured. Drug microparticles produced by SAA can be semi-crystalline or amorphous depending on the process condition; a micronized drug surface area ranging from about 4 to 5 m2/g was also observed. The "in vitro" activity of both untreated and SAA processed glucocorticoids was tested on the release of pro-inflammatory cytokines from stimulated cells. The results shown that SAA-glucocorticoids have retained the activity of the parent untreated compounds and, in the case of dexamethasone, SAA processing improves drug performance.     

Griseofulvin micronization and dissolution rate improvement by supercritical assisted atomization

Supercritical assisted atomization (SAA) was used to micronize griseofulvin (GF), selected as a model compound, to verify the performance of this innovative process. SAA is based on the solubilization of supercritical carbon dioxide in a liquid solution containing the drug. The ternary mixture is then sprayed through a nozzle and microparticles are formed as a consequence of the enhanced atomization. Precipitation temperature and drug concentration in the liquid solution were studied to evaluate their influence on morphology and size of precipitated particles. A good particle size control was obtained and GF spherical particles with mean diameters ranging from 0.5 to 2.5 microm were produced with a narrow particle size distribution. Processed GF was characterized by high-performance liquid chromatography-UV/vis, headspace-gas chromatography-flame ionization detection, differential scanning calorimetry, BET and X-ray analyses. No drug degradation was observed and a solvent residue (acetone) less than 800 ppm was measured. GF microparticles showed good stability and surface areas ranging from about 4 to 6 m(2) g(-1); moreover, the micronized drug retained the crystalline habit. GF capsules were formulated with starch and used to compare the dissolution rate of SAA-processed and conventional jet-milled drug. A faster dissolution and a better reproducibility of the dissolution profile were observed for SAA-processed GF.     

Design and production of gentamicin/dextrans microparticles by supercritical assisted atomisation for the treatment of wound bacterial infections

In this work, the supercritical assisted atomisation (SAA) is proposed, for the first time, for the production of topical carrier microsystems based on alginate–pectin blend. Gentamicin sulphate (GS) was loaded as high soluble and hygroscopic antibiotic model with poor flowability. Particularly, different water solutions of GS/alginate/pectin were processed by SAA to produce spherical microparticles (GAP) of narrow size (about 2 μm). GS loading was varied between 20% and 33% (w/w) with an encapsulation efficiency reaching about 100%. The micronised powders also showed high flow properties, good stability and constant water content after 90 days in accelerated storage conditions. The release profiles of the encapsulated drug were monitored using vertical diffusion Franz cells to evaluate the application of GAP microsystems as self-consistent powder formulation or in specific fibres or gels for wound dressing. All formulations showed an initial burst effect in the first 6 h of application (40–65% of GS loaded), and in particular GAP4 produced with a GS/alginate/pectin ratio of 1:3:1, exhibited the ability to release GS continuously over 6 days. Antimicrobial tests against Staphylococcus aureus indicated that GS antibiotic activity was preserved at 6 days and higher than pure GS at 12 and 24 days for all SAA formulations, especially for GAP1.     

A critical appraisal of the utility of the serum anticholinergic activity assay in research and clinical practice

The serum anticholinergic activity (SAA) assay was originally designed to quantify the anticholinergic burden of drug exposure. The same assay has been used to measure the anticholinergic activity of standard drug solutions. There are limitations to the use of the assay in research and in applying these findings to clinical practice. Assays of standard drug solutions do not account for pharmacokinetic differences among drugs, which limits the interpretation of such measurements. In addition, emerging evidence has suggested that anticholinergic medications may not be the only cause of elevated SAA. Despite these limitations, elevated SAA has been consistently associated with cognitive impairment and delirium in a number of research settings. Such findings have prompted investigators to consider the potential application of the SAA assay in research and in clinical practice. Therefore, the objectives of this review are to summarize the current literature involving the SAA assay, describe the relative merits and shortfalls of the SAA assay as a research tool, and discuss the potential for use of the SAA assay as a clinical tool.     

Serum amyloid A induces WISH cell apoptosis

AIM: Serum amyloid A (SAA) is an important mammalian acute reactant. Here, we aim to investigate the effect of SAA on apoptosis and its mechanism of action in human amniotic WISH cells. METHODS: The expression of formyl peptide receptor (FPRL1), which is reported as a SAA receptor, was tested using RT-PCR and ligand binding assay with radio-labeled FPRL1 ligand. The effect of SAA on proliferating cell population was evaluated by thymidine incorporation assay. The protein phosphorylation levels and caspase-3 activity were detected by Western blot assay. RESULTS: SAA inhibits thymidine incorporation in human amniotic WISH cells. A SAA-induced decrease of proliferating cell population was accompanied with nuclear condensation and caspase-3 activation in WISH cells, suggesting that SAA induces WISH cell apoptosis. Since FPRL1 has been reported as a SAA receptor, we investigated the effects of several FRPL1 agonists on a proliferating cell population in WISH cells. Among the tested FPRL1 agonists, only SAA induced a decrease of proliferating cell population in WISH cells. On the downstream signaling of SAA, we found that SAA stimulated extracellular signal-regulated kinase and p38 kinase, which were not inhibited by pertussis toxin (PTX), ruling out the role of PTX-sensitive G-proteins. Furthermore a SAAinduced decrease of proliferating cell population was not affected by PTX, suggesting that SAA inhibits WISH cell apoptosis in a PTX-sensitive G-proteinindependent manner. A SAA-induced decrease of a proliferating cell population was completely blocked by PD98059 and SB203580, suggesting that mitogenactivated protein kinase activities are essentially required for the process. CONCLUSION: SAA is a novel inducer for WISH cell apoptosis, and the PTX-insensitive pathway is involved in the process.     

主要贮存条件对苦杏仁质量的影响

目的 :了解主要贮存条件对苦杏仁质量的影响。方法 :采用重量法和滴定法进行正交试验。结果 :炮制、温度、贮存时间对苦杏仁苷含量有显著影响 ;温度对苦杏仁酸值有显著影响 ;温度、湿度、贮存时间对苦杏仁过氧化值有显著影响。结论 :苦杏仁最佳贮存条件为制干燥后2℃～8℃冷藏 ,贮存时间越短越好。     

Therapeutic potential of plasma membrane-derived microparticles

In the past, plasma membrane-derived microparticles were considered “cellular dust.” According to the literature, circulating levels of microparticles are increased in several cardiovascular diseases associated with inflammation, suggesting that microparticles are linked to deleterious effects such as endothelial dysfunction or thrombosis. However, very recent studies have shown that under several conditions microparticles can transfer biological messages between cells. Indeed, microparticles act as vectors of key information to maintain cell homeostasis or to favor cell repair and induce angiogenesis. For instance, microparticles of platelet origin are able to repair myocardial injury after myocardial infarction. Also, we have shown that engineered microparticles generated from human activated/apoptotic T cells promote angiogenesis through the up-regulation of adhesion proteins and pro-angiogenic factors in human endothelial cells. Interestingly, the effects induced by these microparticles on the formation of capillary-like structures, expression of adhesion molecules, and pro-angiogenic factors are reversed after silencing of the Sonic Hedgehog (Shh) morphogen pathway. In addition, the same type of microparticles is able to induce neo-vascularization in an ischemic hindlimb model. These effects are, at least in part, mediated by Shh and nitric oxide production. Taking into consideration these results and the most recent data concerning the ability of microparticles to transmit genetic information between cells through mRNA transfer, it is plausible that plasma membrane-derived microparticles could serve as tools with veritable therapeutic potential.     

Serum anticholinergic activity in patients following cardiac surgery and healthy individuals following amitriptyline application

The serum anticholinergic activity (SAA) is used as a marker for cognitive impairment. Here, two studies have been performed characterizing the SAA profile. In Study 1 the endogenous SAA in relation to the total serum protein concentration was monitored for 24 h in five healthy individuals and compared with that in four inpatients following cardiac surgery. In Study 2 the SAA of seven healthy individuals was assessed following a single amitriptyline dose. In both studies SAA was assessed by an ex vivo assay. In Study 1, the absolute SAA varied in a wide range of 1.2 and 14.5 atropine equivalents (AEs) over 24 h. A circadian pattern was not observed. The mean total serum protein concentration, but not the SAA, was significantly lower in inpatients than in healthy individuals. In Study 2, the SAA increased following amitriptyline to a maximum. The mean SAA increased by 6.39 AE at the amitriptyline peak concentration. High SAA variability showed a low statistical relation to amitriptyline concentrations. Both studies characterize the SAA as an individual parameter not affected per se by surgery or clinical care and poorly correlated with the total serum protein concentration. The relation with amitriptyline concentration helps to quantify SAA values towards a better understanding of the clinical implications and limitations of SAA changes.     

Antimetastatic potentials of salvianolic acid A on oral squamous cell carcinoma by targeting MMP‐2 and the c‐Raf/MEK/ERK pathway

The metastasis of oral squamous cell carcinoma (OSCC) is one of the most important causes of cancer‐related deaths. Thus, various therapeutic strategies have been developed to prevent the metastasis of OSCC. Salvianolic acid A (SAA), a traditional Chinese medicine, has antithrombosis, antiplatelet, anti‐inflammation, and antitumor activities. Here, we provide molecular evidence indicating that SAA exerts its antimetastatic effects by markedly inhibiting the invasion and migration of oral squamous SCC‐9 and SCC‐25 cells. SCC‐9 and SCC‐25 cells were treated with various concentrations of SAA to further investigate the precise involvement of SAA in cancer metastasis. The results of zymography, and Western blotting indicated that SAA treatment may decrease matrix metallopoteinase‐2 (MMP‐2) expression. SAA also inhibited p‐c‐Raf, p‐MEK1/2, and p‐ERK1/2 protein expression. In addition, treating SCC‐9 cells with U0126, a MEK‐specific inhibitor, decreased MMP‐2 expression and concomitantly inhibited cell migration. Our findings suggested that SAA inhibits the invasion and migration of OSCC by inhibiting the c‐Raf/MEK/ERK pathways that control MMP‐2 expression. Our findings provide new insights into the molecular mechanisms that underlie the antimetastatic effect of SAA and are thus valuable for the development of treatment strategies for metastatic OSCC.