薄膜分散法制备白藜芦醇长循环热敏前体脂质体及其表征研究

目的:对白藜芦醇长循环热敏前体脂质体制备的研究以及对其性质进行分析。方法:先用薄膜分散法制备白藜芦醇长循环热敏脂质体后,再用冷冻干燥法来制备白藜芦醇长循环热敏脂质体的前体。采用电势测定仪、HPLC等方法对该脂质体的包封率、粒径、稳定性、载药量、电位、释放度等来展开系统的检查。结果:白藜芦醇长循环热敏前体脂质体水合后形成白藜芦醇长循环热敏脂质体,粒径均值为(107.9±3.6)nm,Zeta电位的均值为(-12.2±1.6)m V,包封率可达89.4%;该脂质体在相变温度42℃下药物释放达到94%以上。结论:采用长循环热敏来制备的白藜芦醇前体脂质体含量与包封率检查方法准确、快速、简单且方法简便易行。载药量大,包封率好,工艺比较稳定。本实验可为新型白藜芦醇静脉注射用热敏脂质体的研究提供基础。     

紫杉醇长循环热敏前体脂质体的制备与表征

目的:研究紫杉醇长循环热敏前体脂质体的制备并对其性质进行考察.方法:采用薄膜分散法制备紫杉醇长循环热敏脂质体,再用冷冻干燥技术制备紫杉醇长循环热敏前体脂质体;采用激光粒度仪考察粒径和Zeta电位;采用高效液相色谱法研究其含量与包封率;并考察脂质体的体外释药特性.结果:紫杉醇长循环热敏前体脂质体水合后形成紫杉醇长循环热敏脂质体,粒径均值为(108.6 ±3.6)nm,Zeta电位的均值为(-12.2±1.8)mV,包封率可达96.2％;该脂质体在相变温度42℃下药物释放达到95％以上.结论:紫杉醇长循环热敏前体脂质体的制备工艺稳定,载药量大,包封率高,具有良好的热敏性;含量及其包封率测定方法简单、快速、准确.本实验可为紫杉醇静脉注射用新制剂的开发提供研究基础.     

依托泊苷长循环脂质体工艺处方设计与优化的研究

目的优化依托泊苷长循环脂质体的制备处方及工艺。方法以两亲性聚乙二醇一二硬脂酰磷脂乙醇胺为修饰体，采用薄膜超声．挤压法制备空白长循环脂质体；铵离子梯度法包封依托泊苷，制备依托泊苷长循环脂质体。以包封率为考察指标，采用正交设计法优化依托泊苷长循环脂质体的制备处方及工艺。结果优化后的依托泊苷长循环脂质体的工艺和处方：药脂比例为1：5tool·mol^-1、胆固醇与磷脂比例为0．3：1（W／w）、硫酸铵离子浓度为200mmol·L%^-1、包封温度为55℃。长循环脂质体平均粒径均小于1μm，药物平均包封率86．45％。结论该方法包封率高、粒径小且分布较窄，简便易行。     

依托泊苷隐形脂质体的制备及其质量评价

采用薄膜分散法制备空白脂质体,以PEG2000-DSPE为修饰材料、硫酸铵梯度法包封依托泊苷,减压冷冻干燥制得依托泊苷隐形脂质体。以包封率、载药量和6h累积释放率为指标综合评价,得优化处方为依托泊苷-大豆磷脂重量比1∶15,胆固醇-大豆磷脂重量比1∶6,硫酸铵浓度225mmol/L,包封温度70℃。平均包封率为(83.92±3.65)%,粒径(124.5±26.9)nm,ζ电位(-39.50±1.04)mV。     

鬼臼毒素衍生物脂质体处方和制备工艺优选

目的:优选鬼臼毒素衍生物5-氟尿嘧啶乙酸鬼臼酯(5-FPE)脂质体处方和制备工艺。方法:采用薄膜超声分散法制备5-FPE脂质体,以包封率为指标通过正交试验法优选制备处方和工艺,并考察制备的脂质体的包封率、载药量、形态、粒径分布、Zeta电位及在25、4℃条件下存放10d后的体外稳定性。结果:确定了最优处方和工艺,以此制备的3批脂质体的平均包封率为66.45%,平均载药量为7.97%,粒径均值为284.7nm,平均Zeta电位为—22.15mV;脂质体存放10d后包封率下降,但在4℃条件下存放的脂质体的包封率变化比25℃的更小。结论:以优选处方和工艺制备5-FPE脂质体具有可行性,可为进一步的制剂研究提供基础。     

全反式维甲酸前体脂质体的制备及体外评价

目的:制备维甲酸前体脂质体,并对其体外性质进行考察。方法:采用乙醇注入结合冷冻干燥法制备前体脂质体;微柱离心-高效液相色谱法测定脂质体的包封率;并进一步对其粒径、Zeta电位、血浆释放率及乙醇残留量进行测定。结果:所制备的前体脂质体包封率为95.2%,Zeta电位为-(28.4±17.5)mV,粒径为(170±29)nm,乙醇残留量为3.98%。结论:乙醇注入结合冷冻干燥法制备的维甲酸前体脂质体包封率高,粒径均匀,稳定性好。     

依托泊苷隐形前体脂质体的构建及家兔体内药动学研究

构建依托泊苷隐形前体脂质体，并考察其在家兔体内的药动学。采用薄膜分散法构建窄白隐形脂质体；硫酸铵梯度法包封依托泊苷；结合真空冷冻干燥技术构建依托泊苷隐形前体脂质体。采用凝胶色谱法测定脂质体包封率；透射电镜观察脂质体的形态；电泳光散射技术测定Zeta电位与粒径分布；以市售依托泊苷注射液和普通脂质体为参比制剂，评价其在家兔体内药动学特点。脂质体平均包封率为83．92％±3．65％，粒径为（124．5±26．9）nm，Zeta电位为（-39．50±1．04）mV，家兔单剂量静脉注射1．5mg／kg依托泊苷制剂后呈二室模型特征，依托泊苷隐形前体脂质体的T1/2β为（19．26±3．16）h，AUC为（26．04±3．53）μg／h／mL；注射液的T1/2β为（0．94±0．21）h，AUC为（0．98±0．26）μg／h／mL；普通脂质体的T1/2β为（7．99±1．36）h,AUC为（11．65±1．70）μg/mL。构建的隐形前体脂质体包封率高，且延长了依托泊苷在血液中的循环时间。     

葛根素前体脂质体的质量考察

目的:制备葛根素前体脂质体,并对制剂质量进行考察。方法:采用山梨醇载体沉积法制备葛根素前体脂质体,并对制剂的形态学、包封率、粒径分布、体外释药、稳定性等性质进行考察。结果:本实验制备的脂质体形态多为圆形或椭圆形,平均粒径为278nm,Zeta电位为-17.5mV,包封率为(43.5±1.3)%,体外释药符合一级动力学方程,常温放置稳定。结论:葛根素前体脂质体包封率较高,具有一定的缓释效果,稳定性较好。     

脒修饰的包载荧光探针香豆素-6脂质体的制备

目的研究3,5-二-十五烷氧基苯甲脒(DBH)修饰的香豆素-6脂质体的制备工艺,并初步考察该脂质体的体外释放性能和肾小球靶向性。方法首先合成DBH。再以其为配基,胆固醇、大豆磷脂为载体材料,采用薄膜分散-超声法制备脒修饰的载香豆素-6荧光探针脂质体,考察其粒径分布、Zeta电位、包封率及体外累积释药率。结果脒基修饰的香豆素-6脂质体形态圆整,粒径分布为120.7±2.4 nm,Zeta电位为12.6±1.6 m V,包封率为99.7%±1.8%,体外的48 h累积释药量小于2%。结论脒基修饰的香豆素-6脂质体的制备工艺简便易操作,包封率高,性质稳定。     

唑来膦酸阳离子脂质体的制备及其体外特性表征

目的制备唑来膦酸阳离子脂质体,并对其体外特性进行表征。方法采用薄膜分散法制备唑来膦酸阳离子脂质体,以包封率、载药量、平均粒径、Zeta电位为评价指标,对处方及工艺进行单因素考察,并对其体外特性进行表征。结果确定处方工艺为DPPC与DC-Chol比例为3∶1,PBS水化体积10 m L,旋转蒸发时间60 min,超声均化5 min,制备得到的阳离子脂质体的平均粒径、聚分散指数、包封率、载药量和Zeta电位分别为(106.76±1.94)nm,0.262±0.027,(38.54±0.99)%,(3.42±0.27)%,+(42.37±2.60)m V,唑来膦酸阳离子脂质体体外释药具有缓释靶向特性,药物释放曲线符合Weibull方程模型。结论采用薄膜分散法制备的唑来膦酸阳离子脂质体具有较高的稳定性,为其药动学和药效学研究奠定了基础。     

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.