吸附和包埋法制备洛美沙星淀粉微球及其体外释放比较研究

目的制备盐酸洛美沙星淀粉微球,并对其体外释药模式进行研究。方法以盐酸洛美沙星为模型药物,采用吸附载药法和包埋载药法制备了载药淀粉微球,通过测定微球载药量、包封率和在不同的释放介质中的体外释放情况,对上述2种方法制备的载药微球进行质量评价。结果吸附法制备的载药微球的平均载药量为14.54μg·mg^-1,药物包封率为39.72%;而包埋载药法制备的淀粉微球的平均载药量为19.32μg·mg^-1,药物包封率为48.95%。体外释药特性研究表明它们具有缓释特性,其中包埋载药法制备的淀粉微球比吸附载药法制备的淀粉微球有更好的缓释能力,在不同的释放介质中释药曲线也有所不同,在模拟胃液中累计释药量只能得到70%;而在模拟肠液中累计释药量能达到80%以上。结论吸附载药法和包埋载药法制备的载药淀粉微球都具有缓释作用,但后者体外释药具有更明显的缓释效果。     

吸附和包埋法制备洛美沙星淀粉微球及其体外释放比较研究

目的 制备盐酸洛美沙星淀粉微球,并对其体外释药模式进行研究。方法 以盐酸洛美沙星为模型药物,采用吸附载药法和包埋载药法制备了载药淀粉微球,通过测定微球载药量、包封率和在不同的释放介质中的体外释放情况,对上述2种方法制备的载药微球进行质量评价。结果 吸附法制备的载药微球的平均载药量为14.54 µg·mg^-1,药物包封率为39.72%;而包埋载药法制备的淀粉微球的平均载药量为19.32 µg·mg^-1,药物包封率为48.95%。体外释药特性研究表明它们具有缓释特性,其中包埋载药法制备的淀粉微球比吸附载药法制备的淀粉微球有更好的缓释能力,在不同的释放介质中释药曲线也有所不同,在模拟胃液中累计释药量只能得到70%;而在模拟肠液中累计释药量能达到80%以上。结论 吸附载药法和包埋载药法制备的载药淀粉微球都具有缓释作用,但后者体外释药具有更明显的缓释效果。     

利福平丝素蛋白载药微球的制备及性能研究

目的通过测定利福平丝素蛋白微球的载药量、包封率及释放度,考察乳化转速、有机溶剂与丝素蛋白溶液比例,对微球的制备方法进行优化,筛选微球的最佳制备方法。方法采用乳化法制备利福平丝素蛋白微球,以不同转速、有机溶剂与丝素蛋白溶液不同比例分别制备利福平丝素蛋白微球,采用扫描电镜观察微球的形态,用紫外分光光度法测定微球的载药量、包封率及释放度,以形态、载药量、包封率及释放度为指标,筛选微球的最佳制备方法。在此基础上,采用最佳处方制备3批利福平丝素蛋白微球,对微球的形态、粒径、包封率、载药量和释放度进行考察。结果有机溶剂与丝素蛋白溶液体积比为4∶1、转速为200 r·min^-1时所得利福平丝素微球形态均匀,近似球形,载药量和包封率较高,所得载药微球有较好的缓释作用。以最佳处方制得微球载药量为66.1%±0.87%,包封率为87.80%±2.23%。结论有机溶剂与丝素蛋白溶液体积比为4∶1、转速为200 r·min^-1时载药量、包封率和释放度较好,故选择此处方为利福平丝素蛋白微球的最佳制备处方。     

顺铂聚乳酸微球的制备及体外释药

以聚乳酸为载体，用溶剂挥发法制得顺铂聚乳酸微球。选择聚乙二酵浓度、油／水相体积比、聚乳酸浓度、乳化时间、理论载药量5个因素，每个因素选择5个水平，用均匀设计安排实验。并以微球表面形态、粒径大小及分布、载药量、包封率为指标优化微球的制备工艺。按优化条件制得的微球算术平均径为48．62μm，载药量为15．1％，包封率为50．1％，体外释放符合一级动力学方程。     

丹皮酚聚乳酸羟基乙酸微球的制备及体外释药考察

目的:制备丹皮酚聚乳酸羟基乙酸(PLGA)微球,考察其体外释药过程。方法:以丹皮酚为芯材,以PLGA为载体,采用乳化溶剂挥发法制备丹皮酚PLGA微球;以聚乙烯醇质量分数、PLGA质量浓度、药物与PLGA质量比及水油相体积比为考察因素,以包封率和载药量的综合评分为评价指标,采用正交试验优选制备工艺;扫描电镜和光学显微镜观察微球的外观和粒径,并测定其体外释药过程。结果:优选的工艺为聚乙烯醇质量分数0.9%、PLGA质量浓度60g/L、药物与PLGA质量比1∶3、水油相体积比1∶10。制得的微球球型规则,表面平滑,平均粒径为(31.75±0.13)μm。微球的载药量为(21.16±0.51)%,包封率为(66.91±1.62)%,8h体外累积释药量为37%。结论:所选工艺可用于制备丹皮酚PLGA微球,可为缓释药物传递系统的开发提供参考。     

正交试验优选羧甲基壳聚糖-醋甲唑胺纳米微球的制备方案

目的：制备羧甲基壳聚糖载药纳米微球,醋甲唑胺为模型药物,测量药物的包封率和纳米微球形态.方法：采用乳化交联法,在微乳液的基础上制备载药纳米微球,对可能影响药物包封率的处方因素进行优化设计,筛选出最优配方.结果：羧甲基壳聚糖溶液的浓度对包封率有显著性影响,三聚磷酸钠溶液浓度和醋甲唑胺药量对包封率未见影响.优化方案的载药纳米微球包封率为49.36％,其电镜下为较规整的球型纳米微球,平均粒径386.0 nm.结论：采用乳化交联法,可形成较高包封率的羧甲基壳聚糖-醋甲唑胺纳米微球.     

盐酸维拉帕米缓释微球的制备及其质量评价

目的:制备维拉帕米缓释微球,并对其进行质量评价.方法:采用低温喷雾干燥法制备盐酸维拉帕米缓释微球,评价内容包括:微球的粒径及其分布、微球含药量、载药量和包封率、收率以及不同pH值下的释放速率.结果:成功制备了盐酸维拉帕米缓释微球,平均收率为28.97%,所得微球55%以上的粒径在3.0~5.0μm,载药量为26.11%,包封率为76.40%.结论:微球的体外累积释放度完全符合Higuchi方程,初步证实该微球的释放属于骨架溶蚀性过程.     

莲心总碱-阿霉素明胶微球的制备研究

目的制备莲心总碱-阿霉素明胶微球。方法采用乳化交联法制备莲心总碱-阿霉素明胶微球,用均匀设计对其制备工艺进行优化。结果莲心总碱-阿霉素明胶微球的最优制备条件为：明胶浓度：22.5%,明胶与药物质量比为1∶20,油水相体积比为1∶17.5,搅拌速度：900 r.min-1,25%戊二醛溶液用量：50μL/0.6 g明胶,Span-80用量：2%。按优化工艺参数制得的载药微球呈圆球形,表面光滑,总载药量为：2.56%,包封率为：66.44%,90%的微球分布在10-100μm。结论采用优化工艺条件制备的莲心总碱-阿霉素明胶微球,载药量较大,包封率较高,粒径分布相对集中,形态较好。     

盐酸川芎嗪羧甲基壳聚糖丝素蛋白微球的制备和体外释放特性

摘要：目的:制备一种包载盐酸川芎嗪的羧甲基壳聚糖丝素蛋白微球,以期延长药物的释放时间。方法:采用乳化-化学交联法制备盐酸川芎嗪羧甲基壳聚糖丝素蛋白微球;采用高效液相色谱法测定盐酸川芎嗪的含量;采用Box-Behnken设计-效应面法优化载药微球的制备工艺;考察盐酸川芎嗪注射液和载药微球的体外释放特性。结果:优化的制备工艺条件为:丝素蛋白质量浓度3.0 mg·ml-1、盐酸川芎嗪质量浓度2.0 mg·ml-1、搅拌速度600 r·min-1;制得的载药微球的粒径为（34.4±2.3）μm、包封率为（67.6±1.3）%（n=4）,与软件模型预测值接近,偏差绝对值均小于5%。盐酸川芎嗪注射液中的药物在60 min内已完全释放;而载药微球在30 min内药物快速释放,60 min后药物释放速率较缓慢,180 min时完全释放。载药微球在6种释放介质中的体外释放过程均符合Higuchi方程,体现出良好的缓释特性。结论:优化后的盐酸川芎嗪羧甲基壳聚糖丝素蛋白微球制备工艺简便易行,微球形态圆整,包封率载药量较高,体外释放具有缓释特性。     

载药蒙脱石/丙烯酸树脂微球的制备与体外释放性能的研究

目的以丙烯酸树脂为膜材制备载药蒙脱石/丙烯酸树脂微球并考察其体外释放性能。方法以盐酸倍他洛尔为模型药物,采用O/O溶剂挥发法制备蒙脱石载药微球,通过正交实验设计,考察柠檬酸三乙酯及甘油用量、乳化剂与膜材比例及用量、内外相体积比等因素对微球载药量、包封率、体外释放性能的影响,采用扫描电镜对其外观形态进行表征。结果所得微球外观圆整,粒径分布较均匀,平均粒径为20.7μm,平均载药量为14.31%±0.47%,平均包封率为94.35%±1.01%。结论该法制备载药蒙脱石丙烯酸树脂微球是可行的,体外释放研究表明微球具有一定的缓释作用。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.