磁性载体在药物传递系统中的应用

靶向制剂又称靶向给药系统,被称为第四代给药方法,是指载体将药物通过局部给药或全身血液循环而选择性地浓集定位于靶组织、靶器官、靶细胞或细胞内结构的给药系统.靶向给药系统从方法学上大体可分为三类:被动靶向药物传递系统、主动靶向药物传递系统和物理化学靶向传递系统[1].     

抗癌中药靶向制剂概述

靶向给药系统亦称靶向制剂(targeted drug delivery sys- tem,TDDS),是指给药后能使药物主动地或被动地选择性浓集定位于病变组织、器官、细胞或细胞内结构的新型给药系统。按载体的不同可分为脂质体、微粒、纳米粒(毫微粒)、复合型乳剂等。靶向制剂可使药物到达靶区,提高疗效,降低毒副作用,是近年来国内外药品开发的热点。我国中药     

羧甲基壳聚糖及其复合纳米粒子作为药物载体的应用

靶向给药是指将药物选择性输送至特定生理部位、器官、组织或细胞,并在该靶部位发挥药物治疗作用,提高药物的治疗指数。药物载体缓慢释放则是指能够延长药物在靶部位的作用时间,减少药物在达到疗效期间所产生的降解和损失,     

给药系统进展概述(下)

二、靶向给药系统(Targeting Drug Delivery System) 目前药物治疗全身性疾病是通过各种途径给药,达到一定的血药浓度分布于全身而产生治疗作用,这种治疗方法最大的缺陷是缺乏选择性。如某些疾病只局限于某个部位或器官,则到达的药物仅一小部分,大部分药物未发挥作用,某些强烈的药物往往在起治疗作用的同时产生毒副作用,严重地影响药物的治疗价值。靶向给药系统可提高药物     

主动靶向脂质体研究进展

目的 介绍主动靶向脂质体最新研究进展。方法 查阅近年来国内外相关文献,对主动靶向脂质体的表面修饰、配体选择及应用进行进行总结和归纳。结果 主动靶向脂质体的表面修饰有三种方法：作为组份直接制备;键合到脂质体表面;后插入法。主动靶向脂质体可以将药物传递到靶组织、靶向细胞或靶细胞器,提高药物的生物利用度,而不增加对正常组织或细胞的毒性,是近年研究最为广泛的主动靶向给药系统。结论 主动靶向脂质体是一种非常有前途的给药系统。     

未来药物制剂发展新技术(下)

靶向释药系统 靶向给药系统是根据生物药剂学设想,利用某种载体聚集于作用部位指向给药,可使药物进入所期望的组织或细胞,它包括药物—载体、药物—抗体共扼物,如以脂质体、微球毫微囊、静脉乳剂和磁性药物作载体的各类靶向制剂。 这是一个理想的包括释放和定向传递的药物治疗系统,它能够达到所有预期目标,即在确定的时程内以预定速率在机体特定部位释放一种或多种药物。目前以应用脂质体技术制备靶向制剂和应用单     

环糊精在靶向给药系统中的应用

近年来,为了设计一种能在特殊器官、组织和细胞等部位集中有效释放药物的新型给药系统,国内外药剂工作者做了不懈的努力,其中利用环糊精(CD)制备靶向给药系统的研究也日渐增多。由于CD包合物在水中处于主客分子动态平衡状态,它的解离程度依赖于包合物稳定常数的大小。在吸收部位,包合物解离成游离的CD和药物分子,只有游离的药物分子能够进入体循环。然而,当我们需要将药物靶向定位的时候,这种包合平衡现象往往存在其不利之处,因为当药物到达靶器官或靶组织之前包合物往往已经解离了。为了有效阻止这种解离,国外文献报道最多的是将药物结…     

主动靶向微粒药物载体治疗肿瘤的基础和新进展

配体衍生化的微粒药物载体可以选择性地将微粒靶向特定细胞，因此可以进行集中药物输送。微粒药物载体具有高载荷、不需要与药物共价结合和可以保护药物不与酶作用而失活的优点。内在化配体和靶向血管内肿瘤细胞和肿瘤血管内皮细胞的微粒药物载体在动物模型上表现出了好的效果。一些主动靶向微粒载体已经或即将进行临床试验。具有严格细胞选择性的细胞渗透肽的发现表明，这一方法在不久的将来会取得进一步的完善。     

免疫细胞靶向递送机制与载药技术研究进展

免疫细胞介导的药物靶向递送系统是使用免疫细胞为载体,利用其天然的组织或器官趋向性将药物选择性递送至特定病灶部位的制剂.本文系统介绍了免疫细胞的迁移级联特性,单核/巨噬细胞、中性粒细胞、T细胞和NK细胞等免疫细胞的类型及其作为药物递送载体的主要特点,以及免疫细胞与纳米制剂技术相结合的靶向递送载药策略,为同类研究提供参考.     

半乳糖受体介导的肝靶向药物研究进展

肝脏疾病是临床上的常见病和多发病,其药物治疗主要依靠药物分子到达肝脏病变部位,杀灭致病病毒、修复受损组织或消除疾病症状。1906年Enrilich首先提出靶向给药的概念,肝靶向给药系统(1iver-targetingdrugdelivery system)可将药物有效输送至肝脏病变部位,减少其全身分布,减少     

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.