兰索拉唑脂质体的制备及性质考察

目的研究兰索拉唑阳离子脂质体的制备方法并考察其体外释放行为及稳定性等。方法采用正交设计筛选处方;采用乙醇注入法制备兰索拉唑脂质体;采用超滤法测定其包封率;采用透射电镜观察脂质体的外观形态;采用粒径分析仪和Zeta电位仪分别测定脂质体的粒径和Zeta电位;采用透析法考察脂质体的释放规律。结果制得的脂质体包封率约为(80±1.23)%(n=3);脂质体的形态为粒径均匀的球形和类球形;粒径为(184±21)nm(n=3),Zeta电位为(36.1±5)mV(n=3);脂质体的体外释放符合一级方程,具有较好的稳定性。结论优选得到的脂质体处方和制备工艺合理,制剂性质稳定,其体外释放具有缓释特点。     

兰索拉唑脂质体的制备及其药剂学性质考察

目的:研究兰索拉唑阳离子脂质体的制备方法并考察其药剂学性质。方法:采用正交设计筛选处方,乙醇注入法制备兰索拉唑脂质体;超滤法测定其包封率;用透射电镜观察脂质体的外观形态,并用粒径分析仪和Zeta电位仪分别测定脂质体的粒径和Zeta电位;进一步考察脂质体的释放规律。结果:所得脂质体包封率约为(80±1.23)%;形态为粒径均匀的球形和类球形,粒径为(184±21)nm,Zeta电位为(36.1±5)mV;脂质体的体外释放符合一级方程;具有较好的稳定性。结论:优选得到的脂质体处方和制备工艺合理、稳定,其体外释放具有缓释特点。     

芒柄花素包合物脂质体的制备及质量评价

目的:制备芒柄花素(FMN)包合物脂质体,并评价其质量。方法:以薄膜分散法制备FMN包合物脂质体,考察所制脂质体的外观形态、粒径、Zeta电位、包封率以及体外释放行为。结果:所制FMN包合物脂质体的粒径为(255.34±12.87)nm、Zeta电位为(25.32±3.51)m V、包封率为(81.63±0.79)%(n=3)、24 h的累积释放度为56.12%。结论:本方法成功制得具有良好缓释效果的FMN包合物脂质体,且质量符合相关标准。     

长循环吗啡脂质体的制备及质量评价

摘要：目的:制备长循环吗啡脂质体,优化制备方法,并对制剂质量进行初步评价。方法:建立HPLC法测定吗啡含量的方法;通过单因素考察、正交试验筛选制备最优工艺;测定包封率、体外释放特性、水合粒径和Zeta电位。结果:选择p H梯度法进行制备;最优工艺为磷脂比为4∶1,药脂比为1∶50,孵化温度为50℃,孵化时间为30 min;制得的脂质体包封率为(47.0±1.2)%,水合粒径为(144.3±5.0) nm,Zeta电位为(-63.4±4.6) m V;体外释放试验中,长循环吗啡脂质体表现出明显的缓释作用。结论:制得的脂质体粒径适宜,稳定性好,具有体外缓释作用,为研究吗啡新剂型提供打下基础。     

灯盏花素阳离子脂质体的制备

目的：制备灯盏花素阳离子脂质体和普通脂质体并对其相关性质进行考察。方法：采用薄膜分散法制备灯盏花素脂质体;以包封率为指标,通过正交试验对处方进行优化。考察灯盏花素普通脂质体和阳离子脂质体的体外释放行为。结果：制备的灯盏花素阳离子脂质体性质稳定,包封率为（76.42±1.973）%,平均粒径为（186±35） nm,Zeta电位为（48.9±9.83） mV。灯盏花素普通脂质体和阳离子脂质体的释放过程的拟合方程分别为lnln［1/(1-Q)］=0.779 7lnt-2.318 7(r=0.973 9)和lnln［1/(1-Q)］=0.355 3lnt-3.197(r=0.989 9)。结论：确定了最优处方,制备得到包封率较高且状态稳定的灯盏花素阳离子脂质体。     

水溶性壳聚糖包覆多西他赛纳米脂质体的制备及性能研究

目的:制备羧甲基壳聚糖包衣多西他赛纳米脂质体,并考察其体外释放度。方法:采用薄膜分散法制备多西他赛阳离子脂质体,并用不同浓度的羧甲基壳聚糖包覆阳离子脂质体;用超滤法测定其包封率;用激光电位粒径测定仪分别测定其Zeta电位和粒径大小,并用透射电镜观察其形态;用透析法考察其体外释药性质。结果:所制的羧甲基壳聚糖包覆的脂质体包封率达99.98%;Zeta电位为-12.8 mV,平均粒径为(150±17)nm。结论:本实验制备的羧甲基壳聚糖包衣多西他赛纳米脂质体具有高包封率,粒径大小均匀,体外能显著延缓药物释放的性质。     

多西紫杉醇脂质体的制备及稳定性考察

目的:制备多西紫杉醇脂质体并对其稳定性进行考察。方法:采用薄膜-超声分散法制备脂质体,利用高效液相色谱法测定其主药含量,并考察其粒径、Zeta电位、包封率等指标及在室温条件下密封放置2wk与4℃下冰箱中保存6mo的稳定性。结果:所得脂质体粒径小而均匀,粒径均值为(138.8±1.1)nm,Zeta电位为(2.25±0.2)mV,包封率均在70%以上;多西紫杉醇检测浓度线性范围为0.0325～2.600mg·mL-1(r=0.9993);平均回收率为100.91%(RSD=1.38%,n=3);稳定性考察各项指标均无明显改变。结论:所制制剂包封率较高,稳定性良好。     

盐酸多柔比星脂质体的制备及体外质量评价

目的：制备盐酸多柔比星脂质体并进行体外质量评价,以期实现自制脂质体质量与市售盐酸多柔比星脂质体注射液Doxil一致,并为其生物体内等效及产业化提供研究基础。方法：采用乙醇注入法结合硫酸铵梯度法制备盐酸多柔比星脂质体,以包封率为评价指标通过单因素筛选和正交试验优化制备工艺,以市售Doxil为参比制剂,对比最优工艺制得的脂质体与市售Doxil的微观结构、粒径大小及分布、Zeta电位、相变温度、包封率等理化指标,考察最优工艺制得的脂质体与市售Doxil在加速条件的体外释放及储存条件下稳定性情况。结果：自制盐酸多柔比星脂质体最优制备工艺为高速剪切速率13 000 r·min^-1,挤出3次,载药孵育温度65℃,载药孵育时间60 min,最优工艺制得的脂质体与市售Doxil外观均为椭圆形,平均粒径分别为（90.81±0.58） nm （n=3）和（89.05±0.66） nm （n=3）,分布较为均匀,Zeta电位分别为（-41.9±1.8） mV （n=3）和（-44.9±4.2） mV （n=3）,相变温度范围相同,包封率分别为98.0%和97.9%,体外释放较为一致,稳定性好。结论：采用最优工艺制备的盐酸多柔比星脂质体制备工艺可行,与市售Doxil相比,理化指标及体外释放无明显差异,自制脂质体体外质量良好,符合实验预期。     

齐墩果酸/PLGA-TPGS纳米粒的制备及其体外释放行为研究

目的:制备齐墩果酸/乳酸羟基乙酸共聚物-水溶性维生素E衍生物(PLGA-TPGS)纳米粒(OPN)并考察其体外释放情况。方法:用自制的PLGA-TPGS为载体材料,采用超声乳化-溶剂挥发法制备OPN,考察其粒径、Zeta电位、载药量、包封率、体外累积释放率。结果:所制OPN的平均粒径为(202.4±1.2)nm,Zeta电位为(-21.5±2.2)mV,载药量为(27.65±2.27)%,包封率为(92.52±2.15)%,其在含1.0%十二烷基硫酸钠的磷酸盐缓冲液(pH7.4)中呈两相释放,432h时累积释放率为(93.8±2.9)%。结论:所制OPN质量稳定、可控,具有明显的体外缓释作用。     

pH梯度法结合逆向蒸发法制备氟尿嘧啶脂质体

目的：以pH梯度法结合逆向蒸发法制备氟尿嘧啶脂质体,并评价其质量。方法：采用pH梯度法结合逆相蒸发制备氟尿嘧啶脂质体,以包封率为指标进行处方优化;用Sephadex G-50葡聚糖凝胶柱分离-高效液相色谱法测定氟尿嘧啶脂质体的包封率;以激光散射粒径分析仪测定脂质体的平均粒径及Zeta电位,透射电镜观测形态,并初步考察脂质体在室温和4℃冷藏条件下的稳定性。结果：制得的氟尿嘧啶脂质体外观形态圆整,平均粒径为282nm,Zeta电位为-25．9mV,平均包封率为75．39％,4℃冷藏条件下贮存脂质体的稳定性要明显优于室温贮存。结论：运用pH梯度法结合逆向蒸发法能制备包封率较高的氟尿嘧啶脂质体。     

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.