热熔挤出技术提高水飞蓟素溶出度的初步研究

目的:研究热熔挤出技术是否提高难溶性药物溶出度.方法:以难溶性水飞蓟素为模型药物,以泊洛沙姆-188为亲水性载体,采用热熔挤出技术和熔融法分别制备挤出物和固体分散体,比较两者的差示扫描量热(DSC)图谱和累积溶出曲线.结果:挤出物是分散程度较高的固体分散体,DSC图谱中药物的吸热峰均消失,载体泊洛沙姆-188的吸热峰向低温方向移动,挤出物中的移行程度大于固体分散体;药物在90 min时从挤出物中溶出90.63%,而在固体分散体中的溶出量为71.06%.结论:热熔挤出技术可提高水飞蓟素的溶出度,且效果优于熔融法.     

热熔挤出法制备联苯双酯固体分散体的工艺

目的应用热熔挤出技术制备难溶性药物联苯双酯(bifendate,DDB)的固体分散体,提高DDB的溶出度。方法以共聚维酮(S630)(PVP,N-乙烯基-2-吡咯烷酮和醋酸乙烯酯以质量比为60∶40的比例合成的水溶性共聚物)、PEG6000、丙烯酸树脂Ⅳ为亲水性载体辅料,采用同向双螺杆热熔挤出技术制备DDB固体分散体。比较不同载体挤出物的差示扫描量热图谱和累积溶出曲线,从而判断热熔挤出法对提高DDB溶出度方面的作用。结果采用热熔挤出技术制备的固体分散体可以显著的提高DDB的溶出度。结论采用HME方法制备DDB固体分散体可以显著提高药物的溶出度。     

热熔挤出技术制备吡罗昔康固体分散体

目的采用热熔挤出技术制备难溶性药物吡罗昔康固体分散体,来提高其溶出速率。方法以共聚维酮(PVP-VA64)为亲水性载体材料,聚乙二醇6000为增塑剂,采用热熔挤出技术制备吡罗昔康固体分散体。通过比较差示扫描量热图谱和累积溶出曲线,来表征和评价所制备的固体分散体。结果所制备的固体分散体溶出速率较物理混合物均显著提高。结论热熔挤出技术适用于制备吡罗昔康固体分散体,药物是以无定型分散在载体中,溶出度得到显著提高。     

喷雾干燥法制备阿司匹林固体分散体及其胶囊制备与体外特性研究

目的 制备阿司匹林固体分散体及其胶囊,提高其溶出度。方法 以聚乙烯吡咯烷酮(PVP K 30)为载体,采用喷雾干燥法制备阿司匹林固体分散体,测定溶出度,采用X-射线衍射和扫描电镜(SEM)考察药物在载体中的分散状态,测定比表面积;制备阿司匹林固体分散体胶囊,考察胶囊的体外溶出度。结果 与阿司匹林原料药、阿司匹林物理混合物相比,阿司匹林固体分散体中药物的溶出度均有显著提高,且载体比例越大,药物溶出越快,但药物和载体比例达1∶6以上时,溶出度增加不再明显。阿司匹林以无定型或分子形式高度分散在载体中,药辅比在l∶6时,阿司匹林固体分散体比阿司匹林原料药的比表面积增大3.2倍;制成固体分散体胶囊后,30 min时药物累积溶出度达99.8%。结论 该固体分散体制备工艺可行,制备的胶囊质量可控。     

磷脂固体分散体对槲皮素溶出促进作用的研究

目的研究磷脂固体分散体对槲皮素溶出的促进作用。方法用溶剂法制备了不同比例的槲皮素的磷脂固体分散体 ,与其相应的物理混合物及槲皮素的PVP或PEG4 0 0 0 (1∶1)固体分散体并进行了溶出的对比研究。结果所制得固体分散体均可改善槲皮素的溶出 ,而质量比为 1∶1的槲皮素 磷脂固体分散体的溶出促进作用最为显著。DSC和X射线粉末衍射的研究表明 ,在质量比为1∶1的槲皮素 磷脂固体分散体中 ,槲皮素以无定形的状态分散于载体磷脂中 ,其熔点吸热峰消失。结论槲皮素溶出度的增大与其无定形的存在状态、磷脂对其的润湿作用以及磷脂在水中可形成脂质体有关     

非洛地平固体分散体的制备和体外溶出度考察

目的应用固体分散技术,提高非洛地平的体外溶出度。方法以PVPK30、Lutrol F68、Tween80(与吸附剂,如PVPP)为载体,分别采用溶剂法、熔融法、溶剂蒸发-沉积等技术制备非洛地平固体分散体,考察不同载体对固体分散体溶出度的影响。并着重考察以Tween 80为增溶剂,不同种类吸附剂为载体对固体分散体外观、溶出度的影响。应用差示热分析和X射线衍射鉴别药物在载体中的存在状态。结果采用不同载体和方法制备的非洛地平固体分散体均能明显促进药物的溶出,溶出速度依次为Tween 80>Lutrol F68>PVPk30。其中m(药物)∶m(Tween 80)∶m(PVPP)=1∶4∶5时,溶出速度最快,1 h累积释放率达90%以上。差示热分析固体分散体中药物吸热峰前移或消失,X射线衍射固体分散体中药物的结晶衍射峰消失,推测药物在载体中以无定形或分子形式存在。结论制备非洛地平固体分散体可以提高其体外溶出度,尤其是含有表面活性剂的固体分散体可进一步提高药物的溶出。     

热熔挤出法增加布洛芬的溶出度并掩盖其苦味

目的:制备布洛芬固体分散体,以增加布洛芬的溶出度并掩盖其苦味。方法:取布洛芬原料药与丙烯酸树脂Eudragit EPO,以1∶1.5(w/w)混合,采用热熔挤出法制备布洛芬固体分散体。用差示扫描量热法和粉末X射线衍射法分析布洛芬在Eudragit EPO中的分散状态。测定固体分散体、物理混合物和市售布洛芬片剂的溶出度,并评价布洛芬固体分散体的掩味效果。结果:布洛芬晶体结构的特征峰在差示扫描量热和粉末X射线衍射图中消失。在磷酸盐缓冲液中,固体分散体的溶出速度大于物理混合物和布洛芬片。志愿者对布洛芬固体分散体的味觉评价优于物理混合物和布洛芬原料。结论:热熔挤出法制备的Eudragit EPO固体分散体能增加布洛芬的溶出度,并有明显的掩味效果。     

阿司匹林固体分散体及其胶囊的制备与体外溶出度研究

目的:制备阿司匹林固体分散体及其胶囊,并研究其体外溶出度。方法:以聚乙烯吡咯烷酮为载体,采用喷雾干燥法制备阿司匹林固体分散体,比较阿司匹林原料药、阿司匹林与载体不同比例的物理混合物和固体分散体的溶出度;采用X-射线衍射和扫描电镜考察药物在载体中的分散状态,测定比表面积;考察阿司匹林固体分散体胶囊的体外溶出度。结果:与阿司匹林原料药、阿司匹林物理混合物比较,阿司匹林固体分散体中药物的溶出度均有提高,且载体比例越大,药物溶出越快,但药物-载体比例达1∶6以上时,溶出度增加不再明显;阿司匹林以无定型或分子形式高度分散在载体中;药物-载体在l∶6时,阿司匹林固体分散体比阿司匹林原料药的比表面积增大3.2倍;制成固体分散体胶囊后,30 min时药物累积溶出度达99.8%。结论:该固体分散体制备工艺可行,制备的胶囊质量可控。     

格列喹酮固体分散体的制备及溶出度测定

目的:制备格列喹酮固体分散体并考察其体外溶出性。方法:以聚乙烯吡咯烷酮K30(PVP)、聚乙二醇6000(PEG)为载体,溶剂熔融法和溶剂法制备格列喹酮固体分散体,并与原料药比较体外溶出度。结果:载体比例越大,药物溶出愈快。载体为PVP所制固体分散体的体外溶出行为总体优于载体为PEG者。格列喹酮-PVP固体分散体(1∶7)10min内体外溶出度达到70%以上,优于格列喹酮原料药。结论:成功制备了格列喹酮固体分散体。     

热熔挤出法制备苯氧乙酸吡嗪酯类化合物FC固体分散体的研究

目的 利用热熔挤出法制备难溶性的药物苯氧乙酸吡嗪酯类化合物FC固体分散体,提高FC的溶出度.方法 选用亲水性的PVPK30、PEG6000、Poloxamer188作为载体辅料,采用热熔挤出技术制备FC固体分散体.通过比较药物FC在不同载体挤出物中的差示扫描量热图和累积溶出曲线图,来判断热熔挤出技术对提高难溶性药物FC溶出度方面的作用.结果 利用热熔挤出法制备的固体分散体能够显著的提高FC的溶出度.结论 用热熔挤出法制备的FC固体分散体,在提高难溶性药物的溶出度方面具有显著的作用.     

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.