克拉霉素缓释包衣微丸的制备及体外释放度研究

目的制备克拉霉素缓释包衣微丸,并对其体外释放度进行考察。方法采用挤出滚圆技术制备克拉霉素含药微丸。以优化的丙烯酸树脂类Eudragit NE30D和Eudragit L30D-55混和水分散体为包衣材料,采用流化床包衣技术,制备缓释包衣微丸。考察自制缓释微丸的体外释药速率,并与市售的克拉霉素缓释胶囊进行比较。结果通过释药行为的评价,得到优化的包衣处方为5∶1的Eudragit NE30D和Eudragit L30D-55混和包衣材料,其体外释放行为在不同的pH溶出介质中与市售制剂产品没有明显差异,体外释药过程符合一级释放模型。结论采用挤出滚圆和流化床技术,以及优化的Eudragit NE30D和Eudragit L30D-55混和水分散体包衣材料,成功制备了克拉霉素缓释包衣微丸。     

磷酸川芎嗪丙烯酸树脂水分散体包衣小丸的体外释放研究

目的：研究磷酸川芎嗪丙烯酸树脂水分散体包衣缓释小丸的体外释药。方法：采用丙烯酸树脂RS30D和丙烯酸树脂RL30D混合液包衣制备磷酸川芎嗪缓释小丸，并考察包衣混合液中两种丙烯酸树脂水分散体比例、包衣增重、溶出介质pH对磷酸川芎嗪包衣制剂体外释药的影响。结果：随着包衣液中丙烯酸树脂RL30D/丙烯酸树脂RS30D比例增大、包衣增重降低、溶出介质pH增大，释药速率加快。结论：包衣液中丙烯酸树脂RL30D/丙烯酸树脂RS30D比例、包衣增重、溶出介质pH均显著影响制剂药物释放。     

非诺贝特缓释微丸的制备及释放度研究

目的：制备非诺贝特缓释微丸。方法：采用BZJ-360M离心包衣造粒机制备微晶纤维素空白丸核和非诺贝特含药素丸，并在此基础上进行丙烯酸树脂水分散体（Eudragit NE 30D）包衣。用释放度测定法考察影响药物释放的各种因素，对包衣微丸体外释药机制进行研究。结果：包衣材料为Eudragit NE 30D，增重3％时包衣微丸呈现良好的缓释效果，体外释药过程基本符合Higuchi方程：Q=0．436＋30．316t^1/2／（r=0．9997）。结论：成功的制备了非诺贝特缓释微丸。     

盐酸美金刚缓释微丸的制备及体外释放度考察

目的:制备盐酸美金刚缓释微丸,并对其体外释放度进行考察。方法:采用流化床包衣法制备盐酸美金刚载药微丸,再用Eudragit RL 30D和Eudragit RS 30D进行包衣,制成盐酸美金刚缓释微丸,并考察盐酸美金刚缓释微丸的体外释药行为。结果:体外释放度试验显示,制备的盐酸美金刚缓释微丸在24 h内平稳释放且释药完全,释药规律符合零级释药模型。结论:用本方法制备的盐酸美金刚缓释微丸具有缓释效果。     

赵海茵1，赵燕敏1，包强2，陈锋1

目的制备水飞蓟宾葡甲胺缓释微丸,考察其体外释放度。方法采用离心造粒粉末层积法制备微晶纤维素空白丸芯。以收率及粒径分布为评价指标,考察载药微丸工艺。以Eudragit RS 30D/RL 30D水分散体混合物进行包衣,探讨包衣微丸的释药特征。结果水飞蓟宾葡甲胺缓释微丸的最佳处方与工艺条件为：黏合剂1%羟丙甲基纤维素（HPMC）溶液、黏度5 MPa•s,主机转速130 r•min－1,喷气压力0.3 MPa,浆泵转速6 r•min－1,抛光时间3 min,包衣增重7%,Eudragit RS/RL比例4：1。体外释放接近一级释放模型,释药速度符合Fick’s第一定律。结论离心造粒法制备水飞蓟宾葡甲胺缓释微丸工艺简单,具有缓释效果。     

扑热息痛缓释微丸的制备

目的制备扑热息痛缓释微丸,并对其体外释药情况进行研究。方法采用挤出滚圆法制备扑热息痛素丸,在流化床内采用丙烯酸树脂水分散体对其包衣,制备扑热息痛缓释微丸。用释放度测定法考察影响药物释放的各种因素,对包衣微丸体外释药机理进行研究。结果包衣材料为丙烯酸树脂NE30D(Eudragit NE30D),质量分数增加6%时包衣微丸在pH 6.18的磷酸盐缓冲液中呈现良好的缓释效果,体外释药过程基本符合Higuchi方程:Y=31.213t1/2+0.425(r=0.993 2)。结论采用挤出滚圆法和丙烯酸树脂流化床包衣,成功地制备了扑热息痛缓释微丸,其体外释药缓慢、持续平稳。     

洛索洛芬钠缓释微丸的制备与体外释放度研究

摘 要 目的：制备洛索洛芬钠缓释微丸,并考察其体外释药行为。方法: 采用挤出滚圆法制备洛索洛芬钠载药丸芯,再用Eudragit RL 30D和Eudragit RS 30D 进行包衣,制成洛索洛芬钠缓释微丸,并考察缓释微丸的体外释药行为。结果: 以Eudragit RL 30D和Eudragit RS 30D的比例为20∶80作为洛索洛芬钠载药丸芯的缓释包衣材料,包衣增重为20%,增塑剂用量为10%,滑石粉用量为45%时,制备的洛索洛芬钠缓释微丸在12 h内能够平稳释药且释药完全。结论:制备的洛索洛芬钠缓释微丸释药行为较好,有望应用于工业生产。     

酒石酸美托洛尔缓释微丸的制备及处方因素考察

目的：选用Eudragit RS 30 D与Eudragil RL30D两种包衣材料，制备日服2次的酒石酸美托洛尔缓释徽丸，并对其处方因素进行考察。方法：采用Glatt流化床底喷溶液上药法制备载药微丸，考察缓释聚合物Eudragit RS 30D与Eudragit RL 30D的不同质量配比（2：3，7：3和9：1）、聚合物包衣增重（10％，20％和30％）以及增塑利嗣量（10％，20％和40％）和放置时间对药物释放的影响。结果：当Eudragit RS 30D与Eudragit RL 30D的质量比为9：1，聚合物包衣增重为20％，增塑剂用量为20％时，药物的释放行为符合中国药典对缓释制剂释放度的相关规定。结论：通过调整Eudragit RS 30D与Eudragit RL 30D之间的比例，或提高聚合物包衣增重等手段，能使酒石酸美托洛尔载药徽丸具备较理想的缓释效果。     

盐酸普拉克索缓释微丸的制备及体外释放度考察

目的:制备盐酸普拉克索缓释微丸。方法:采用挤出-滚圆法制备盐酸普拉克索微丸,再用EudragitRL30D和EudragitRS30D进行包衣,最终制成盐酸普拉克索缓释微丸,并用高效液相色谱法测定药物含量。结果:体外释放度实验显示,制备的盐酸普拉克索缓释微丸在24 h内平稳释放且释药完全。结论:用本方法制备的盐酸普拉克索缓释微丸体外释药平稳,释药规律符合一级释放模型。     

对乙酰氨基酚缓释微丸的制备及释放度研究

目的制备对乙酰氨基酚缓释微丸,考察包衣处方等因素对微丸释放度的影响。方法采用离心-造粒法制备微晶纤维素空白丸核和对乙酰氨基酚微丸,并在此基础上采用甲基丙烯酸树脂(Eudragit RS30D/RL30D)包衣,制备对乙酰氨基酚缓释微丸。采用HPLC法测定对乙酰氨基酚缓释微丸释放度,单因素筛选包衣处方的优化参数。结果以Eudragit RS30D/RL30D比例为15:1(w/w),包衣增重为10%,柠檬酸三乙酯占包衣材料量的25%,滑石粉占包衣材料量的40%为包衣液,制备的对乙酰氨基酚释微丸释药曲线具有较好的缓释特性。结论制备的对乙酰氨基酚缓释微丸具有缓释特性且操作简便、工艺稳定。     

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.