阿克拉霉素A固体脂质纳米粒冻干针剂体外释药规律研究

目的 :研究阿克拉霉素A固体脂质纳米粒 (ACM -SLN)冻干针剂的体外释放规律。方法 :采用动态透析技术测定ACM -SLN冻干针剂的体外释药百分率 ,用不同的方程对其释药百分率进行拟合。结果与结论 :一级动力学方程和Weibull模型拟合结果较好 ,ACM -SLN冻干针剂的释药规律最接近一级动力学方程     

大蒜素微球体外释放研究

目的:研究聚乳酸大蒜素微球释放规律.方法:采用动态透析技术研究聚乳酸大蒜素微球的体外释药性能,并用高效液相色谱法测定大蒜素含量,以累计释药百分率进行不同模型的拟合.结果:聚乳酸大蒜素微球的释放曲线符合双相动力学方程.结论:聚乳酸大蒜素微球具有良好的缓释作用.     

黄芩苷固体脂质纳米粒体外释放研究

目的:研究黄芩苷固体脂质纳米粒的体外释药规律。方法:采用动态透析技术研究黄芩苷固体脂质纳米粒的体外释药性能,并用高效液相色谱法测定黄芩苷含量,以累积释药百分率进行不同模型的拟合。结果:黄芩苷固体脂质纳米粒的释放曲线符合Hixon-crowell方程,t≈3h。结论:黄芩苷固体脂质纳米粒具有良好的缓释作用。     

盐酸川芎嗪眼用原位温敏凝胶的制备及体外释药特性研究

目的：制备盐酸川芎嗪眼用原位温敏凝胶并对其体外释药特性进行考察。方法采用泊洛沙姆407和泊洛沙姆188为温敏基质制备眼用温敏凝胶,采用无膜溶出模型,研究药物在某一时间的累积释放百分率与时间的变化,对曲线进行拟合分析,研究川芎嗪的体外释放特性。结果所制得凝胶为均匀稍带黏性的澄清溶液,该制剂的体外释放行为遵循零级动力学方程（r ＝0．9887）,由 Ritger －Peppas 方程拟合的 n 值为0．7533。结论盐酸川芎嗪眼用温敏凝胶体外释药是由药物扩散和凝胶溶蚀双重机制控制。     

阿柔比星A聚乳酸毫微粒冻干针剂的研制及体外药物释放规律的研究

研究阿柔比星Ａ聚乳酸毫微粒（ＡＣＲＢ－Ａ－ＰＬＡ－ＮＰ）冻干针剂的制备,并对其体外释药进行考察。根据低共熔点测定结果,以及外观、色泽、再分散性等质量参数为指标,制备出ＡＣＲＢ－Ａ－ＰＬＡ－ＮＰ冻干针剂,采用动脉透析法研究其体个释放规律。结果,制得的ＡＣＲＢ－ＡＰＬＡ－ＮＰ冻干针剂色泽均匀,再分散性良好。其体外释药可用３种方式表达。提示ＡＣＲＢ－Ａ－ＰＬＡ－ＮＰ冻干针剂有明显的缓释特征。     

美乐托宁缓释片在不同介质中的释放试验

目的:制备美乐托宁缓释片,以国外上市制剂美乐托宁缓释片为参比制剂,考察自研制剂和参比制剂在不同pH释放介质中体外释放行为的相似性及体外释药机制。方法:采用释放度测定法转篮法的装置进行体外释放实验,用HPLC法测定释放度,采用f2相似因子对2种制剂释放曲线的相似度进行评价,并进行释放行为模型的拟合。结果:在不同pH的释放介质中,自制制剂释放度曲线与参比制剂比较,f2相似因子均大于50;美乐托宁缓释片在4种释放介质中体外释药拟合模型更接近一级方程、Higuchi方程和Peppas方程。结论:参比制剂与自制制剂在不同pH释放介质中的体外释放一致,释放机制为扩散释药。     

盐酸青藤碱肠溶控释片体外释放及其机制的探讨

目的:制备一种盐酸青藤碱膜控型口服给药系统,并对其体外释放规律及机制进行研究。方法:以丙烯酸树脂RS、RL为包衣材料、HPMCP-HP55为致孔剂对骨架片芯进行包衣而得。对影响释药行为的体外释放条件进行考察,利用电镜观察控释片释药前后衣膜的形态学变化,并通过考察释药途径,对控释片体外释药行为进行数学模型拟合,并分析其释药机制。结果:释放介质的pH对体外释药有显著影响,药物主要通过致孔剂所形成的孔道释放。体外释药曲线基本符合零级方程(R2=0.995 6,AIC=-31.651 7)。结论:体外释放表明,本控释片受除介质pH以外的其他条件影响都很小,在pH6.8磷酸盐缓冲液中的释药曲线符合零级方程,并主要受膨胀机制的影响。本研究可为水溶性药物膜控型控释片体外释药机制的探讨提供实验参考。     

西罗莫司脂质体的体外释放研究

目的:研究西罗莫司脂质体的体外释放特性。方法:建立反相高效液相色谱法测定西罗莫司含量;采用反透析法,以500mL 20%乙醇为释放介质,考察24 h不同时间西罗莫司脂质体的体外累积释放率,利用药物释放模型方程拟合释放曲线。结果:西罗莫司检测浓度的线性范围为0.5～20 μg.mL~(-1)(r=0.999 8),平均回收率为99.42%,RSD=1.23%;脂质体前4 h的释药速率快,累积释放率为50%,之后释药相对缓慢,24 h的累积释放率为80%,释放曲线符合一级动力学方程。结论:西罗莫司脂质体具有一定缓释效应,其体外释放属于浓度依赖型渗透释药。     

阿昔洛韦缓释片在不同介质中的释放研究

目的:研究阿昔洛韦缓释片在不同介质中的体外释药特性。方法:以转篮法进行溶出度研究;采用紫外分光光度法在254nm波长下测定阿昔洛韦缓释片在4种释放介质即0.1mol·L-1盐酸液、pH6.8磷酸盐缓冲液、蒸馏水和由0.1mol·L-1盐酸液(前2h)与pH6.8磷酸盐缓冲液(2h后)组成的替换介质中的12h内的释放度,并进行释放行为模型的拟合。结果:阿昔洛韦缓释片在盐酸液中的释放速度最快,但12h时4种介质中阿昔洛韦皆释放完全;阿昔洛韦在4种介质中体外释药拟合模型更接近Higu-chi方程和Peppas方程。结论:阿昔洛韦缓释片在不同介质中均具有缓释性,释放机制主要为扩散释药。     

尼美舒利亲水凝胶骨架缓释片的制备及体外释放

目的:优化尼美舒利缓释片的制备方法。方法:采用正交试验设计,以体外累积释药百分率为指标,以HPMC(K100-LV CR)、乳糖、PVP(K30)的处方用量作为影响因素筛选缓释片的最佳处方,并测定3批优化处方的体外释放度。结果:优化处方结果为HPMC K100-LV CR为100 mg,乳糖为50 mg,黏合剂为5%PVP无水乙醇溶液3 mL;尼美舒利缓释片在12 h释放量达97%以上,没有时滞、突释等现象。其体外释药动力学符合零级方程。结论:尼美舒利缓释片处方合理,制备工艺可靠,体外释药效果良好,质量可控。     

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.