乙肝清HPMC K4M/PVP K30骨架缓释片的研制与体外评价

目的进行乙肝清HPMC K4M/PVP K30骨架缓释片的研制与体外评价。方法以中药赶黄草和贯叶连翘的提取物为原料药,以HPMC K4M和PVP K30两种粘度不同,水合行为差异较大的亲水高分子材料联合使用作为骨架材料,制备缓释12 h的"乙肝清骨架缓释片"。以"HPMC+PVP K30"总量在处方中的百分量和HPMC在"HPMC+PVP K30"总量中的百分量为考察因素,通过处方单因素考察和星点设计—效应面法进行优化,得到最佳的制剂处方。并通过均一性实验和体外释药行为研究进行体外评价。结果本片剂优化处方中最低HPMC K4M与PVP K30用量不得低于20%。最佳制剂处方为骨架材料HPMC+PVP K30总量占片剂质量的27.03%,HPMC占HPMC+PVP K30总量的49.04%。本处方具有良好的重现性与稳定性;片剂药物释放符合一级释放模型。结论制备了载药量40%的乙肝清提取物缓释片,并优化得到了其最佳的制剂处方。     

五加生化缓释片的制备及体外释放度的研究

目的：筛选五加生化缓释片的最佳制备工艺,并进行体外释放度研究。方法采用正交试验法筛选处方;以羟丙甲基纤维素（HPMC）为骨架材料,制备五加生化缓释片,并对优化的试验结果进行体外释放效果考察。结果最优处方为HPMC K100M为骨架材料,70%乙醇为黏合剂,MCC为填充剂用量40 mg,淀粉为填充剂用量50 mg,采用最佳工艺制备的五加生化缓释片体外释放性能较好,HPMC的规格对药物的释放影响最大。结论本法制备的缓释片比普通片具有明显的缓释作用。该制备工艺简单易行,生产成本低,片剂外观及可压性良好。     

盐酸美金刚缓释片的制备及其体外释放度考察

目的制备盐酸美金刚缓释片,并对其体外释放行为进行考察。方法以HPMC K15M和HPMC K4M为骨架材料压制缓释片。以HPMC(X1)用量和HPMC K15M/K4M用量之比(X2)为考察因素,以盐酸美金刚在2,6和10h的累积释放度Y2h,Y6h,Y10h为考察指标,利用2因素3水平中心复合设计-效应面法优化处方。在4种介质中考察了盐酸美金刚缓释片的体外释药行为。结果最终优化处方中的HPMC用量为片质量的60.0%,HPMCK15M/K4M用量之比为70∶30,所得缓释片在2,6和10h三点的累积释放度符合20%≤Y2h≤30%,40%≤Y6h≤60%和Y10h≥80%的要求,在12h内释放平稳、完全。结论采用中心复合设计-效应面法优化的处方预测性良好,制得的盐酸美金刚缓释片体外释放符合要求。     

琥珀酸 S-美托洛尔缓释片的研制及体外释放特征探讨

目的：研制琥珀酸S-美托洛尔24 h缓释片,考察其体外释放特征,并对其体外释放机制进行初步研究。方法以羟丙基甲基纤维素（ HPMC）为骨架材料制备缓释片,以单因素试验法对缓释片释放因素进行考察,采用正交试验设计选择最佳处方,并对优化处方的释药机制进行探讨。结果最优处方以K100M和K15M规格HPMC的混合物作为骨架材料,质量分数各占总质量的20％,微晶纤维素为填充剂,质量分数占总质量的50％。制备的琥珀酸S-美托洛尔缓释片释放规律符合Ritger-Peppas方程曲线,释药行为是药物扩散和骨架溶蚀协同作用。结论琥珀酸S-美托洛尔缓释片处方合理,有良好的24 h体外释药行为,处方工艺基本满足设计要求。     

离心法制备卡托普利凝胶骨架丸及其体外释放度的研究

目的 制备卡托普利亲水凝胶骨架型缓释丸,并考察其体外释放性能.方法 采用离心法制备卡托普利凝胶骨架丸,在单因素实验的基础上,通过正交试验优化制备的最佳条件,对优化条件下制备的骨架丸进行体外释放度实验,并考察释放机理.结果 骨架材料为HPMC K15M,用量45%时骨架丸呈现良好的缓释效果,体外释药过程基本符合Higuchi方程:Q=5.286+0.502t~(1/2)(r=0.9967).结论 所建方法能成功地制备卡托普利亲水凝胶骨架缓释丸.     

卡托普利混合骨架片的处方筛选及优化

目的:研制混合骨架的卡托普利缓释片.方法:采用两因素六水平的均匀设计法筛选混合骨架片的优化处方,其中,两因素为缓释骨架材料HPMC K4M和蜡质888(Compritol 888);六水平指这两种缓释材料6种不同的用量.结果:最终优化处方中缓释材料HPMC K4M用量为20%,Compritol 888用量为30%.结论:用优化的处方,工艺制备的3批卡托普利缓释片体外释放良好,质量稳定.     

辛伐他汀缓释片制备及体外释放研究

目的制备辛伐他汀凝胶骨架缓释片,对影响药物释放的因素进行考查。方法采用紫外分光光度法测定其体外释放度,应用湿法制粒压片法制备缓释片,以羟丙基甲基纤维素（HPMC）为骨架材料,考察了HPMC规格、用量及其它辅料对药物释放的影响,并进行了正交实验优化及处方和制备方法的验证。结果辛伐他汀缓释片的体外释放受HPMC规格、HPMC用量、粘合剂种类的影响,选择HPMC（K15M）为骨架材料,其与主药质量比为1.5∶1,所制缓释片能持续释药12 h,批间重现性良好。结论该制剂处方合理,制备方法可行,具有良好的缓释效果。     

Box-Behnken效应面法优化尼群地平凝胶骨架缓释片处方

目的对尼群地平凝胶骨架缓释片的处方进行筛选和研究。方法以凝胶骨架基质HPMC K4M和HPMC100LV的用量为考察因素,药物在1、2、4、6、10h的累积释放度Y1h、Y2h、Y4h、Y6h、Y10h为考察指标,利用2因素3水平中Box-Behnken效应面法优化处方。结果联合使用HPMC K14M及HPMC 100LV作为尼群地平缓释片的基本骨架材料,乳糖作为填充剂,硬脂富马酸钠为润滑剂,85%乙醇溶液适量作为黏合剂制成尼群地平缓释骨架片在各时间点释放度符合标准。结论通过Box-Behnken效应面法优化法建立的模型可以用于尼群地平凝胶骨架缓释片处方的优化,所制得的缓释片释放度符合规定。     

烟酸凝胶骨架缓释片的处方工艺研究

目的:优化烟酸凝胶骨架缓释片处方工艺。方法:采用亲水凝胶骨架材料羟丙基甲基纤维素(HPMC)的2种型号K15M、E15-LV及辅料磷酸氢钙的处方用量为因素设计正交试验,以体外释放度为考察指标,优化烟酸凝胶骨架缓释片的处方,并进行批内和批间体外释放度验证试验。结果:优化处方为HPMC(K15M、E15-LV)分别为4%、40%,磷酸氢钙为25%。所制烟酸凝胶骨架缓释片可持续释药12h,批内释放均一性及批间重现性均良好。结论:所选烟酸凝胶骨架缓释片处方合理,工艺简单。     

拉莫三嗪缓释片的制备及体外释放行为考察

目的:改进原研制备工艺,仿制拉莫三嗪缓释片,并考察其体外释放行为。方法:采用羟丙基甲基纤维素(HPMC)E4M CR和HPMC K100LV CR制备缓释骨架片芯,以尤特奇~?L30D-55为肠溶材料包衣,制备拉莫三嗪缓释片。以与原研制剂体外释放度的相似因子f_2为指标,采用单因素法筛选处方中乳糖用量、HPMC E4M CR和HPMC K100LV CR质量比、HPMC用量及包衣增质量。结果:片芯处方为拉莫三嗪50 mg、HPMC K100LV CR 40 mg、HPMC E4M CR 61.4 mg、乳糖128 mg,最佳包衣增质量为3%。自制制剂和原研制剂在含0.5%十二烷基硫酸钠的pH 6.8磷酸盐缓冲液、pH 4.5乙酸-乙酸钠缓冲液和水中的体外释放行为均相似。结论:成功仿制了拉莫三嗪缓释片,且工艺比原研制剂更加简单、易行。     

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.