载环孢素A海藻酸钙-壳聚糖微球的制备及体外释放特性

目的:针对角膜移植术后免疫抑制治疗需求,制备眼部局部给药的小粒径载环孢素A缓释微球,并进行体外释放考察。方法:以海藻酸钠、壳聚糖为载体材料,采用静电液滴工艺,通过向制备体系添加表面活性剂,制备小粒径载环孢素A微球,设计正交试验优化处方工艺,扫描电镜观察微球表面形态,动态透析法考察微球的体外释放特性。结果:所制微球形态良好,粒径分布窄,平均粒径为(12.4±0.8)μm,包封率为(82.8±1.8)%,载药量为(50.1±1.2)%,体外释放行为用Higuchi方程拟合效果最好。结论:采用静电液滴工艺,通过减小制备体系的表面张力,制备了球形度优良、粒径小、包封率和载药量较高的载环孢素A的壳聚糖-海藻酸盐缓释微球,所得制剂的体外释药规律服从扩散机制。     

阿立哌唑缓释微球的制备及体外释放特性的研究

目的 制备阿立哌唑聚乳酸-羟基乙酸共聚物(PLGA)缓释微球并考察其体外释放特性.方法 采用乳化-溶剂挥发法制备阿立哌唑缓释微球,通过正交试验优选最佳处方与制备工艺,并考察其载药量、包封率、粒径、形态和体外释放度.结果 所得微球的载药量为20.28％ ±0.38％,包封率为81.12％±0.02％,平均粒径为19.38 μm,形态圆整,30 d的体外累积释放度达88.73％.结论 所得阿立哌唑缓释微球形态圆整,载药量与包封率较高,具较好的缓释效果.     

去甲斑蝥素壳聚糖微球的制备及其体外释放特性

目的:制备去甲斑蝥素壳聚糖微球,并考察其体外释放特性.方法:以液体石蜡为油相,Span-80为乳化剂,甲醛作为交联剂,采用乳化-交联法制备去甲斑蝥素壳聚糖微球.均匀设计优化制备工艺,扫描电镜观察微球表面形态,动态透析法检测微球的体外释放特性.结果:制备的微球形态圆整,粒径分布较为均匀,平均粒径(25±10)μm,载药量(15.08±2.85)%,包封率(57.80±1.35)%.微球在0.1 mol·L-1HCl、磷酸盐缓冲液(pH值5.3)和生理氯化钠溶液中的释放均遵循Higuchi方程.结论:所优化的制备工艺简单易行,载药量高,缓释作用显著.     

替莫唑胺乳酸-羟基乙酸共聚物微球的制备及表征

采用乳化-溶剂挥发法制备替莫唑胺微球,考察了制备工艺中影响微球粒径、载药量和包封率的主要因素,筛选处方工艺.按优化工艺制得的微球形态圆整,表面光滑,平均粒径62.2μm,载药量7.5%,包封率83.5%,体外试验表明该载药微球有明显的缓释效果.     

尼莫地平壳聚糖微球的制备及其体外释药特性的研究

目的 以壳聚糖为载体材料制备尼莫地平微球,并考察其体外释药特性。方法 以壳聚糖为载体,液体石蜡为油相,戊二醛为交联剂,span80为乳化剂,采用正交设计优化壳聚糖微球的制备工艺,用乳化交联法制备尼莫地平壳聚糖微球。模拟人体肠液的环境进行体外释药研究。结果 通过单因素考察和正交实验,筛选出尼莫地平壳聚糖微球的优化制备工艺和处方,所得微球形态圆整,大小均匀,表面光滑,平均粒径为9.56 μm,载药量为17.82%,包封率为52%。体外释药结果表明,一级动力学方程能较好的对其进行拟合。结论 尼莫地平壳聚糖微球的制备工艺稳定可行,所得壳聚糖微球有良好的缓释效果。     

尼莫地平壳聚糖微球的制备及其体外释药特性的研究

目的以壳聚糖为载体材料制备尼莫地平微球,并考察其体外释药特性。方法以壳聚糖为载体,液体石蜡为油相,戊二醛为交联剂,span80为乳化剂,采用正交设计优化壳聚糖微球的制备工艺,用乳化交联法制备尼莫地平壳聚糖微球。模拟人体肠液的环境进行体外释药研究。结果通过单因素考察和正交实验,筛选出尼莫地平壳聚糖微球的优化制备工艺和处方,所得微球形态圆整,大小均匀,表面光滑,平均粒径为9.56μm,载药量为17.82%,包封率为52%。体外释药结果表明,一级动力学方程能较好的对其进行拟合。结论尼莫地平壳聚糖微球的制备工艺稳定可行,所得壳聚糖微球有良好的缓释效果。     

环丙沙星壳聚糖微球的制备

以戊二醛作为交联剂,采用反相乳化法制备支气管镜介入治疗用环丙沙星壳聚糖微球.采用单因素法和正交试验优化了处方中影响制品外观、平均粒径、载药量和包封率的因素.按优化处方制备的微球外观圆整,平均粒径(142.31±7.85) μm,载药量(14.20±0.61)％,包封率(56.43±1.31)％.体外释放行为符合Higuchi方程,2h和48 h时累积释放率分别为44.3％和92.1％,提示制品具有缓释效果,有利于减少给药频次.     

奥沙普秦壳聚糖-海藻酸钠缓释微球的制备

目的：目的：选择奥沙普秦作为模型药制备壳聚糖-海藻酸钠缓释微球。方法：采用滴制法制备奥沙普秦壳聚糖-海藻酸钠缓释微球，通过正交试验设计优化了处方和工艺，考察其理化特征及体外释药行为。结果：优化处方制得的微球包封率及载药量分别为98．36％和16．26％，平均粒径为（346．6±164．1）μm；1h药物释放达到36％，随后药物的释药行为是一个缓释过程。结论：制得了载药量较大，包封率较高的奥沙普秦壳聚糖-海藻酸钠缓释微球。     

星点设计-效应面法优化去甲斑蝥素壳聚糖-丝素蛋白栓塞微球的制备

目的:制备去甲斑蝥素壳聚糖-丝素蛋白栓塞微球(Norcantharidin-loaded chitosan-fibroin micro-spheres for embolization,NCTD-CS-SF-MS),考察其包封率,载药量及外观形态,并对其体外释放特性进行考察。方法:采用乳化-交联固化法制备NCTD-CS-SF-MS,其中以液体石蜡为油相,壳聚糖(chitosan CS)与丝素蛋白(silk fibroin SF)的物理混合溶液为水相,Span-80为乳化剂,戊二醛为交联剂。星点设计-效应面法优化制备工艺,扫描电镜观察微球表面形态及X-射线衍射(XRD)、差示量热扫描(DSC)表征微球特性。采用体外动态透析法测定微球在不同介质条件下的释药性能。结果:制备的微球形态圆整,大小均匀,平均粒径约(184±5)μm,载药量(15.08±2.85)%,包封率(27.46±1.25)%。微球在0.1 mol.L-1 HCl、PBS(pH=7.4)和生理盐水中的释放均遵循Weibull方程。结论:所优化的制备工艺简单易行,缓释作用显著。     

青蒿琥酯-壳聚糖纳米粒的制备及质量评价

目的:研制青蒿琥酯-壳聚糖纳米粒(ART-CS-NPs)并进行质量评价。方法:采用离子交联法制备ART-CS-NPs,以包封率和粒径为考察指标,通过单因素、正交设计试验优化制备工艺及处方,通过形貌观察、粒径和电位测定、体外释药考察对其进行质量评价。结果:以优化处方、工艺制备的ART-CS-NPs在透射电镜下呈现圆整、均匀的球形微粒,形态规则完整。粒径为(186.8±12.2)nm,PDI为(0.259±0.004),Zeta电位为(+31.7±1.5)mV,包封率为(69.4±1.4)%,载药量为(19.67±0.32)%。ART-CS-NPs体外释放曲线以Higuchi方程拟合结果最好。结论:离子交联法所制ART-CS-NPs形态规则完整,载药量、包封率较高,体外释放具有缓释作用,稳定性较好。     

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.     

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.     

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.