苯巴比妥钠包合物的制备及其在液体制剂中的稳定性

目的：制备苯巴比妥钠包合物并考察其稳定性。方法：采用β-环糊精作为包合剂制备苯巴比妥钠包合物，应用等温加热法，选择40，50，60，70，80℃进行加速稳定性试验考察其在水溶液中的稳定性，应用动力学数据估算有效期，以紫外分光光度法测定苯巴比妥钠含量。结果：选择β-环糊精与苯巴比妥钠的摩尔比为1：2投料进行包合物制备，各温度下苯巴比妥钠及其包合物的消除量时间函数呈线性关系，预测室温下包合物有效期（含量下降5％）为苯巴比妥钠的3．5倍。结论：β-环糊精包合后提高了苯巴比妥钠稳定性。     

注射用奥美拉唑钠溶液的稳定性考察

目的:考察注射用奥美拉唑钠溶液的稳定性.方法:测定溶液的pH值、紫外光谱,采用HPLC法测定溶液中奥美拉唑的含量,定时观察溶液的颜色及澄明度,观察钾、镁、钙离子及pH值对注射用奥美拉唑钠(洛赛克)溶液稳定性的影响及其在常用输液5%葡萄糖注射液、0.9%氯化钠注射液、葡萄糖氯化钠注射液及复方氯化钠注射液中的稳定性.结果:注射用奥美拉唑钠在4种常用输液中于4 h内可保持稳定.pH值对其稳定性具有很大影响,溶液pH值低于7.0时奥美拉唑极不稳定;pH值在7.0～8.0之间时,可出现颜色变化,但降解不明显;而溶液pH值在8.0～10.0之间奥美拉唑在4 h内是稳定的.钾、镁、钙离子不影响注射用奥美拉唑钠水溶液的稳定性.结论:pH值对溶液中奥美拉唑钠的稳定性较大,而钾、镁、钙离子则不影响其稳定性.     

pH值及温度对注射用奥美拉唑钠溶液质量的影响

目的考察pH值及温度对注射用奥关拉唑钠溶液质量和颜色的影响。方法采用高效液相色谱法（HPLC法），在不同时间、不同温度、不同pH值备件下测定溶液中奥关拉唑的含量；测定溶液的pH值，观察其外观色泽，用紫外光谱法测定吸收度。结果pH值对注射用奥关拉唑钠溶液的稳定性影响很大，溶液pH值低于7．0时奥关拉唑钠极不稳定，颜色发生变化，有降解产物产生；而溶液在pH值为9左右时比较稳定，没有颜色变化，紫外吸收值极小。温度对奥关拉唑钠的稳定性影响大，温度越高，时间越长，奥关拉唑钠越容易分解。结论DH值对溶液中奥美拉唑钠的稳定性影响较大，温度对稳定性有一定的影响。     

pH值依赖的帕瑞昔布钠溶液化学稳定性、溶解度和油水分配系数研究

目的研究介质pH值对帕瑞昔布钠(PCX)溶液化学稳定性、溶解度及油水分配系数的影响,为PCX鼻腔给药新剂型的研究提供理论依据。方法建立PCX的HPLC分析方法,研究不同pH条件下药物溶液化学稳定性、溶解度及油水分配系数。结果 pH<6.0时,PCX溶液的化学稳定性较差,当pH≥6.0时,PCX溶液的化学稳定性良好;PCX的溶解度随着介质pH值的增大而增大,在碱性pH下其溶解度较好;PCX的油水分配系数随着pH值的增大而逐渐减小,在酸性pH下,油水分配系数较大,而在碱性pH下,油水分配系数很小。结论 PCX溶液化学稳定性、溶解度及油水分配系数具有明显的pH值依赖性。     

抗氧剂对注射用奥美拉唑钠稳定性的影响

目的探讨抗氧剂对注射用奥美拉唑钠药液稳定性的影响。方法用奥美拉唑钠原料进行碱度试验,结合制剂工艺筛选过程中不同的pH值对药液稳定性的影响,考察抗氧剂与奥美拉唑钠配伍后药液的外观和pH值变化。结果加入抗氧剂后,奥美拉唑钠药液的外观和pH值均符合要求,稳定性提高。结论pH值高低是影响注射用奥美拉唑钠稳定性的主要因素,在一定pH值条件下加入抗氧剂可进一步提高药液稳定性。     

抗氧剂对注射用奥美拉唑钠稳定性的影响

目的 探讨抗氧剂对注射用奥美拉唑钠药液稳定性的影响.方法 用奥美拉唑钠原料进行碱度试验,结合制剂工艺筛选过程中不同的pH值对药液稳定性的影响,考察抗氧剂与奥美拉唑钠配伍后药液的外观和pH值变化.结果 加入抗氧剂后,奥美拉唑钠药液的外观和pH值均符合要求,稳定性提高.结论 pH值高低是影响注射用奥美拉唑钠稳定性的主要因素,在一定pH值条件下加入抗氧剂可进一步提高药液稳定性.     

胰岛素溶液化学稳定性研究

本文用反相高效液相色谱法(RP-HPLC)和高效液相凝胶层析法(GF-HPLC)研究了pH值对胰岛素溶液化学稳定性的影响。稳定性实验采用经典恒温法。实验结果表明pH值是影响胰岛素溶液化学稳定性的重要因素,在酸性溶液中降解反应速率随pH值的降低而增大;而在碱性溶液中则随pH值的降低而减小,即溶液pH值接近胰岛素等电点时其稳定性最好。胰岛素溶液加热降解反应规律符合一级动力学方程。     

关于硝普钠注射液的稳定性

硝普钠水溶液的稳定性随pH 值及遇光情况而变,在偏酸性时稳定性较好。水溶液贮于冰箱及暗处可较好保持稳定。但如遇光线或在高pH 值时则迅速分解。本刊1981年第一期刊登的综述“硝普钠的     

pH值对盐酸吡硫醇水溶液稳定的影响

目的考察pH值对盐酸吡硫醇水溶液稳定性的影响.方法用恒温加速试验法,测定不同温度下不同pH值时盐酸吡硫醇降解的速率常数,得到不同pH值时的降解活化能及不同温度下的最稳定pH值.结果在不同温度下,当pH2时,盐酸吡硫醇水溶液相对最稳定;随着pH值升高,水溶液稳定性迅速降低.结论适当调整溶液的pH值可以显著改善盐酸吡硫醇的化学稳定性,为其制剂学研究提供了部分依据.     

注射用泮托拉唑钠的稳定性考察

目的:考察注射用泮托拉唑钠在4种输液中的稳定性。方法:采用高效液相色谱法测定注射用泮托拉唑钠与4种输液配伍 后在4h内的含量变化,并观察溶液外观;同时考察钾、镁、钙离子及pH值变化对注射用泮托拉唑钠稳定性的影响。结果:注射用泮 托拉唑钠在4种常用输液以及钾、镁、钙离子水溶液中于4h内其含量、外观、pH值、最大紫外吸收波长均无明显改变。溶液pH值 低于7．0时泮托拉唑钠极不稳定;pH值为7．0时,颜色可出现微黄变化,但含量降低不明显;溶液pH值在8．0以上时泮托拉唑钠 在4h内稳定。结论:注射用泮托拉唑钠在4种常用输液以及钾、镁、钙离子水溶液中于4h内可保持稳定,pH值对泮托拉唑钠溶液 的稳定性影响较大。     

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.     

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.     

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.