卡维他洛固体分散体的研制及其体外溶出实验

目的：制备卡维他洛固体分散体,增加其溶解度和溶出速度。方法：以聚乙烯吡咯烷酮（PVP）、聚乙二醇-6000（PEG-6000）为载体,溶剂法和溶剂熔融法制备固体分散体,并进行体外溶出度研究。结果：载体比例越大,药物溶出愈快;且载体比例愈小,差异愈显著。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-6000的固体分散体。结论：本试验所制卡维地洛固体分散体能加速体外溶出,为难溶于水药物提高生物利用度开辟一条途径。     

卡维地洛固体分散体的制备及其体外溶出度的测定

目的 :制备卡维地洛固体分散体 ,提高其溶解度和溶速率。方法 :以聚乙烯吡咯烷酮 (PVP)、聚乙二醇 -6000(PEG -6000)为载体 ,以溶剂法和熔融法制备固体分散体 ,并进行体外溶出度研究。结果 :载体比例越大 ,药物溶出愈快 ;载体比例愈小 ,差异愈显著。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 -6000的固体分散体。结论 :本试验所制卡维地洛固体分散体能加速体外溶出 ,提高生物利用度 ,可用于制备高效制剂     

水飞蓟素增溶方法的比较研究

目的：优选增加水飞蓟素溶解度和溶出速度的最佳方法的条件。方法：以聚乙烯吡咯烷酮（PVP）,聚乙二醇6000（PEG-6000）,PEG-6000与Tween-80混合载体。制备固体分散体;以β-CD,HP-β-CD制包合物,测定溶解度及体外溶出速度,结果：水中溶解度PVP固体分散体大于包合物,载体比例越大,药物溶出愈快。比例相同时,PVP固体分散体溶出最快。结论：PVPK30作为水飞蓟素固体分散体的载体。载药量大。增溶效果显著。     

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。     

卡维地洛固体分散体的制备与溶出度测定

目的：制备卡维地洛固体分散体,增加其溶解度和溶出速度。方法：以聚乙烯吡咯烷酮（PVP）、聚乙二醇－6000（PEG－6000）为载体,溶剂法和溶剂熔融法制备固体分散体,并进行体外溶出度研究。结果：载体比例越大,药物溶出愈快;且载体比例愈小,差异愈显著。载体为PVP所制固体分散体的体外溶出为总体优于载体为PEG－6000的固体分散体。结论：本试验所制卡维地洛固体分散体能加速体外溶出,为难溶于水药物提高生物利用度开辟一条途径。     

卡维地洛固体分散体的初步研制

目的:制备卡维地洛固体分散体并考察其体外溶出度。方法:以聚乙二醇(PEG)、聚乙烯吡咯烷酮(PVP)的混合物(2∶1、1∶2)为载体,采用溶剂熔融法和共沉淀法制备载体与药物不同比例的固体分散体并比较其体外溶出度。结果:药物溶出度随载体比例增加而增加;载体与药物比例越小,固体分散体与药物原料粉之间溶出度差异越显著;PEG∶PVP(1∶2)所制分散体体外溶出行为较优,以3、10、30、60min时溶出百分率进行比较,固体分散体是药物原料粉的3～8倍。结论:所制卡维地洛固体分散体能增加药物体外溶出度。     

甘草黄酮固体分散体的制备及体外溶出性能考察

目的:制备甘草黄酮(LF)-聚乙烯吡咯烷酮K30(PVP K30)固体分散体,并对其进行表征及体外释药性能考察。方法:分别以聚乙烯吡咯烷酮K30(PVP K30)、聚乙二醇(PEG 4000、 PEG 6000)、泊洛沙姆188(F68)以及胶态二氧化硅(SiO2)为载体,采用溶剂法或溶剂熔融法制备固体分散体,考察其体外释药性能,并利用差式扫描量热仪(DSC)、傅里叶变换红外光谱(FT-IR)对固体分散体的结构特征进行表征。结果:以PVP K30为载体制备的固体分散体的体外溶出率优于其他载体制备的固体分散体,且以药物-载体比例1∶5时溶出度最佳。经DSC和FT-IR结果表明,固体分散体中的药物以无定形状态存在。结论:固体分散体技术能显著提高甘草黄酮的体外溶出度。     

水溶性呋喃西林固体分散体配方及工艺研究

目的 利用固体分散技术制备水溶性呋喃西林固体分散体,增加其溶解度.方法 选择聚乙二醇6000(PEG)为载体, 采用熔融法、溶剂-熔融法,按药物与载体1:3、1:6、1:9的比例分别制成不同的呋喃西林固体分散体,将呋喃西林原药与呋喃西林固体分散体进行体外溶出度试验和溶解度试验.结果 呋喃西林固体分散体的体外溶出度和溶解度与呋喃西林原药相比显著增大.结论 选择呋喃西林与聚乙二醇(PEG)-6000(1:6)及溶剂-熔融法作为水溶性呋喃西林固体分散体的配方及工艺,可使呋喃西林的溶解度提高.     

硝苯地平固体分散体制备工艺的研究

目的利用固体分散技术将硝苯地平制成固体分散体,提高其体外溶出速率。方法分别以聚乙二醇6000(PEG6000)、聚乙二醇4000(PEG4000)、聚乙烯吡咯烷酮K30(PVPK30)、泊洛沙姆188(Pluronic F68)等为载体,用熔融法、溶剂法、溶剂-熔融法和喷雾干燥法制备硝苯地平固体分散体。采用差热分析法(DTA)分析药物在固体分散体中的存在状态,并进行体外溶出度试验。结果各种固体分散体均能加快药物的溶出速率,并且随着载体在固体分散体中的比例增大,溶出速率增大。DTA分析显示硝苯地平在PVPK30的固体分散体中以微细结晶存在。结论将硝苯地平制成固体分散体能显著提高硝苯地平的体外溶出速率。     

硝苯地平固体分散体制备工艺的研究

目的利用固体分散技术将硝苯地平制成固体分散体,提高其体外溶出速率。方法分别以聚乙二醇6000(PEG6000)、聚乙二醇4000(PEG4000)、聚乙烯吡咯烷酮K30(PVPK30)、泊洛沙姆188(Pluronic F68)等为载体,用熔融法、溶剂法、溶剂-熔融法和喷雾干燥法制备硝苯地平固体分散体。采用差热分析法(DTA)分析药物在固体分散体中的存在状态,并进行体外溶出度试验。结果各种固体分散体均能加快药物的溶出速率,并且随着载体在固体分散体中的比例增大,溶出速率增大。DTA分析显示硝苯地平在PVPK30的固体分散体中以微细结晶存在。结论将硝苯地平制成固体分散体能显著提高硝苯地平的体外溶出速率。     

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.     

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.