载羟基喜树碱聚乳酸微球的制备与体外释药研究

目的:研究载羟基喜树碱的聚乳酸微球的制备方法并考察其体外释药性质。方法:以PLA为成膜材料,采用改良乳化-溶剂挥发法,制备载羟基喜树碱的聚乳酸微球并优化制备工艺;对载药微球进行表征;超声介导下进行载药微球的体外释药试验。结果:微球粒径在1～7μm,大小均一;羟基喜树碱浓度在10mg.mL-1下,载药微球包封率为62.2%,载药量为1.69%;药物体外释药符合Higuchi方程。结论:采用乳化-溶剂挥发法,以PLA为成膜材料可制得具有较高包封率的羟基喜树碱微球,有望实现降低羟基喜树碱给药量、减少不良反应,提高靶向性的目标。     

阿苯达唑纳米混悬液的冻干工艺优化

目的:优化阿苯达唑纳米混悬液的冻干工艺,制备阿苯达唑纳米微粉。方法:采用冷冻干燥法,以粒径、Zeta电位为指标,对预冻温度和冻干保护剂的种类、配比及质量分散进行单因素试验考察及验证,将液相沉淀法制备的阿苯达唑纳米混悬液,制备成阿苯达唑纳米微粉。结果:预冻温度为-20℃、冻干保护剂为4%葡萄糖-甘露醇(3∶7)时,所制纳米微粉的平均粒径为(208.03±2.13)nm,平均Zeta电位为(-15.53±0.18)m V。结论:该冻干工艺可制得粒径、电位较优的阿苯达唑纳米微粉。     

阿苯达唑聚氰基丙烯酸正丁酯纳米粒的制备、性质及其组织靶向性研究阿苯达唑聚氰基丙烯酸正丁酯纳米粒的制备、性质及其组织靶向性研究

目的制备阿苯达唑聚氰基丙烯酸正丁酯纳米粒（albendazole polybutycyanocrylate nanoparticles，ABZ-PBCA-NP）TDDS给药系统，并考察相关特性及组织分布靶向性。方法种子乳化聚合法制备阿苯达唑纳米粒；等温吸附法考察纳米粒载药特性；动态透析法研究4种制剂的体外释药动力学；同位素标记阿苯达唑纳米粒在小鼠脏器组织分布和生物利用度。结果ABZ-PBCA-NP体外释药遵循Higuchi方程，加入PVP制成的载药纳米粒符合双指数函数。纳米粒的载药方式遵循Langmuir吸附方程。小鼠ig ³H-ABZ-PBCA-NP后, 药物的肝、脾中的靶向指数分别为11.4和3.9，阿苯达唑纳米粒和混悬剂相对生物利用度分别为76.0%和36.9%。结论制备纳米粒加入PVP可使药物具吸附性和分散性，纳米粒载体可降低药物与血浆蛋白结合率，增强药物的肝、脾脏器靶向性和延缓释药。     

羟基喜树碱半固体脂质纳米粒的制备和体外释药特性

目的：制备羟基喜树碱的半固体脂质纳米粒（HCPT-SSLN），初步考察其体外释药规律。方法：采用乳化蒸发-低温固化法制备HCPT-SSLN；用激光粒度仪测定其粒径和ξ电位；考察其混悬液和冻千粉的物理稳定性；用透析法考察其体外释药性质。结果：HCPT-SSLN纳米粒平均粒径为130．5nm，裁药量为2．51％，包封率为79．19％，ξ电位为-33．1mV;室温（25℃）和4℃下放置6个月，纳米粒冻干粉和混悬液外观、粒径及包封率无明显变化；体外释药规律符合Weibull方程lnln[1／（1-Q）]=0．26331nt＋0．0509（R^2=0．9485）。结论：制备的HCPT-SSLN包封率高，稳定性好，大小均匀，体外释药具有缓释特点。     

替莫唑胺壳聚糖缓释微球的制备及体外释药特性

目的:制备替莫唑胺壳聚糖缓释微球,并对其体外释药模式进行研究.方法:以替莫唑胺为模型药物,采用乳化交联法制备壳聚糖微球,两步优化法优化处方和制备工艺.通过测定微球的粒径及其分布、载药量、包封率和体外释放速度对微球进行质量评价.结果:优化工艺制得的微球平均粒径为(3.9±1.6)μm,载药量为(7.1±0.5)%(n=3),包封率为(25.0±0.8)%(n=3),体外释药特性研究具有良好的缓释特性,在0～8 h符合Higuchi方程,Q=11.717 26.951t1/2(r=0.980),8～24 h符合一级释放曲线,lnQ=4.37 0.007 5t(r=0.983).结论:通过优化处方和制备工艺,采用乳化交联法可制备出以壳聚糖为载体、替莫唑胺为模型药物的缓释微球,其体外释药具有明显的缓释作用.     

硝苯地平生物黏附微球的制备及释药机制研究

目的:制备硝苯地平生物黏附微球并考察其体外释药情况。方法:在单因素考察的基础上应用正交设计筛选硝苯地平生物黏附微球的最佳处方,因素为加热温度、聚乙烯醇(PVA)用量、司盘浓度和戊二醛用量,评价指标为累积释药率;考察优化处方所制微球的质量指标如体外黏附力和累积释药率等,研究其释药机制。结果:优化处方工艺为:加热温度60℃、PVA用量0.6 g、司盘浓度5%、戊二醛用量0.6 mL;优化处方所制微球体外黏附力较高,平均载药量约为15%,包封率约为85%,平均粒径约为20μm;微球可持续24 h释药,释药符合Higuchi方程,释药机制符合非Fick扩散机制,即以溶蚀和扩散2种模式释放。结论:硝苯地平生物黏附微球制备工艺简单,具有较好的体外黏附性能和缓释效果。     

胸腺肽明胶微球的制备和体外释药的特性

目的:为提高胸腺肽的生物利用度,增强疗效,制备胸腺肽的明胶微球.方法:用乳化交联法制备胸腺肽明胶微球,正交设计法筛选其最佳制备工艺,Lowry法测定药物的含量,计算微球的载药量、包封率及体外释药量.结果:微球粒径范围为1.0～30.2 μm,平均粒径为14.64 μm,平均载药量为20.20%(w/w),平均包封率为80.82%,其体外释药符合Higuchi方程,稳定性考察实验结果表明其稳定性较好.结论:本法制备的胸腺肽明胶微球粒径分布集中,粒径大小符合设计要求,体外释药有明显的缓释作用,具有良好应用前景.     

阿苯达唑纳米晶体的制备与表征

目的： 采用微射流高压均质-喷雾干燥法技术制备阿苯达唑纳米晶体,并进行表征和体外溶出考察。方法： 釆用高压均质法制备阿苯达唑纳米混悬液,并进一步喷雾干燥得纳米晶体。通过正交试验优化制备工艺;对最佳制备工艺所得纳米晶体进行粒径测定、DSC分析和傅里叶红外图谱分析,并测定其体外溶出度。结果： 微射流高压均质最佳制备工艺条件：在均质温度35℃,103.44 MPa和137.93 MPa下各循环20次,得到纳米混悬液平均粒径为（363.52±1.5） nm。喷雾干燥最佳工艺为：进样速度5 mL·min^-1,进风温度180℃,在此条件下得粉率（66.71±0.96）%,含水量（6.61±0.16）%,平均粒径367.34±0.68 nm。DSC分析及傅里叶红外图谱结果表明制备成纳米晶体后形成新的物象;体外溶出度实验结果表明,纳米晶体的溶出度显著高于原料药和混合物。结论： 微射流高压均质-喷雾干燥工艺,可以制备平均粒径小且较为均匀的纳米晶体;纳米化后形成新的物象,可以明显提高阿苯达唑的溶出性能,利于改善药物的口服吸收,这为阿苯达唑进一步开发提供了依据。     

关节腔注射用氟比洛芬PLGA缓释微球的制备及体外释放特性研究

目的制备关节腔注射用氟比洛芬(FP)缓释微球并研究其体外释药特性。方法以聚乳酸-羟基乙酸共聚物(PLGA)为材料,采用乳化-溶剂挥发法制备微球;正交设计法优化微球的制备工艺;采用透析法研究体外释药特性,UV法测定FP的含量。结果正交试验表明,PLGA的浓度是影响微球包封率的非常显著性因素。微球粒径范围为1.5~24.3μm,平均粒径为10.6μm,载药量为7.1%(W/W),包封率为92.7%,体外释药符合Higuchi方程,释放时间显著延长。结论本法制备的FP微球粒径大小适宜,具有明显的缓释作用,符合关节腔注射给药设计要求。     

吲达帕胺结肠定位释药微球的制备及其体外释放度考察

目的:以羟丙甲基纤维素琥珀酸酯(HAS)为载体材料制备吲达帕胺结肠定位释药微球并考察其体外释放度。方法:根据球晶造粒技术,采用乳化溶剂扩散法制备微球,以收率、载药量、包封率为优化指标,对影响微球制备的因素进行正交试验,通过神经网络遗传算法优选处方及工艺,并对以优化方案制备的微球进行了质量评价。结果:制备的吲达帕胺结肠定位释药微球形态圆整,大小均匀、表面光滑,粒径在50~250μm范围的微球占到92.07%,载药量为15.30%,包封率为95.48%;体外释药试验中,微球在模拟全胃肠不同pH条件下,即先在pH1.2和pH6.8介质中5 h累计释药17.54%,继在pH7.8介质中7 h后累积释药99.75%。结论:本试验筛选的处方及制备工艺可用于制备吲达帕胺结肠微球,且制备的微球能达到结肠定位释药的目的。     

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.

---

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.