葡聚糖凝胶柱色谱法测定阿苯达唑纳米脂质体包封率的方法研究

目的：考察用葡聚糖凝胶柱色谱法测定阿苯达唑纳米脂质体包封率的影响因素。方法：考察大、小2种不同粒径（100～300、50～150μm）的葡聚糖凝胶对样品脂质体的分离效果;以方法回收率和脂质体分离比为综合指标,以凝胶柱内径与葡聚糖填充高度比（A）、洗脱流速（B）及上样量（C）为因素设计正交试验,筛选测定脂质体包封率的最优条件,并进行验证试验。结果：小粒径的葡聚糖凝胶对样品分离效果更好;优选测定条件为A：1.2：5、B：5mL·min-1、C：0.5mL;验证试验中平均脂质体分离比（包封率）为（91.56±0.98）%,平均方法回收率为（98.61±0.44）%（n=3）。结论：所建立的阿苯达唑纳米脂质体包封率测定方法准确、重现性好。     

紫外分光光度法测定黄芩苷脂质体的包封率与渗漏率

目的测定黄芩苷脂质体的包封率与渗漏率。方法采用Sephadex G-50凝胶柱分离游离药物，紫外分光光度法测定黄芩苷脂质体的含量。结果黄芩苷线性范围4～20 μg·mL^-1，r＝0.999 4，加样回收率98.83%，RSD＝2.26%。结论该方法简便易行，准确性高，可用于测定脂质体的包封率与渗漏率。     

尼莫地平纳米脂质体包封率测定方法的研究

目的　建立尼莫地平纳米脂质体的包封率测定方法。方法　以高效液相色谱法为分析手段 ,采用反透析法测定尼莫地平纳米脂质体的包封率。结果　反透析法透析平衡时间为 6h ,游离药物回收率符合要求 ;此法测得自制尼莫地平纳米脂质体的平均包封率为 85 6 9%± 3 13% ,10h内无渗漏 ,方法重现性好。结论　反透析法便捷、准确 ,适用于脂溶性药物尼莫地平纳米脂质体的包封率测定。     

尼莫地平纳米脂质体包封率测定方法的研究

目的　建立尼莫地平纳米脂质体的包封率测定方法。方法　以高效液相色谱法为分析手段 ,采用反透析法测定尼莫地平纳米脂质体的包封率。结果　反透析法透析平衡时间为6h ,游离药物回收率符合要求;此法测得自制尼莫地平纳米脂质体的平均包封率为85.69%±3.13% ,10h内无渗漏,方法重现性好。结论　反透析法便捷、准确 ,适用于脂溶性药物尼莫地平纳米脂质体的包封率测定。     

阳离子交换树脂-高效液相色谱法测定羟喜树碱脂质体包封率

［摘要］目的建立阳离子交换树脂 高效液相色谱（HPLC）法测定羟喜树碱脂质体方法的包封率。方法阳离子交换树脂柱层析法分离脂质体和游离药物,HPLC法测定脂质体中药物的含量,计算包封率。 结果在所选色谱条件下,辅料不干扰测定,羟喜树碱浓度在0.56～11.20 μg&;#8226;mL 1范围内线性关系良好。阳离子交换柱层析法可将脂质体与游离药物有效分离,药物回收率99.4％,加样回收率98.1％。样品的包封率88.3%～91.5％。结论阳离子交换柱层析法便捷、准确,可用于测定羟喜树碱脂质体的包封率。     

苦参碱脂质体的制备与包封率测定

目的 制备苦参碱脂质体并测定其包封率. 方法 采用硫酸铵梯度法制备苦参碱脂质体, 采用葡聚糖凝胶G-100分离苦参碱脂质体和游离苦参碱, 并用高效液相色谱法测定脂质体的包封率. 结果 苦参碱脂质体包封率为33.4%, 苦参碱在0.005～0.500 mg•mL-1范围内线性关系良好（r=0.999 8）. 结论 硫酸铵梯度法制备出包封率相对高的苦参碱脂质体, 高效液相色谱法测定脂质体的包封率简单快速, 方法准确, 重现性好.     

胰岛素柔性纳米脂质体的口腔给药研究

目的探讨柔性纳米脂质体经口腔粘膜转运蛋白多肽类药物的可能性。方法用反相蒸发法制备胰岛素柔性纳米脂质体和普通脂质体,对其包封率、形态和粒径大小进行测定。以家兔为动物模型,口腔给药(bu)后,进行体内降糖实验,同时测定胰岛素水平变化。结果胰岛素柔性纳米脂质体与普通脂质体的包封率分别为(18.9±1.8)%和(22.1±2.2)%;粒径分别为(42±20) nm和(60±34) nm。透射电镜下,胰岛素柔性纳米脂质体的指纹状结构比普通脂质体更多,其他无明显区别。以sc胰岛素溶液(1 U·kg^-1)为对照,bu胰岛素柔性纳米脂质体组(10 U·kg^-1)的药理相对生物利用度为15.59%,相对生物利用度为19.78%,高于bu胰岛素溶液对照组(P<0.05)、胰岛素普通脂质体组(P<0.05)及空白柔性纳米脂质体与胰岛素混合物组(P<0.05)。结论胰岛素柔性纳米脂质体可能成为经口腔粘膜转运蛋白多肽类药物的有效载体。     

紫杉醇纳米脂质体凝胶剂的制备及体外透皮研究

目的制备紫杉醇纳米脂质体凝胶剂,考察其粒径、粒径分布、包封率、体外释放度及透皮特性。方法采用薄膜蒸发高压微射流法制备紫杉醇纳米脂质体,以卡波姆为凝胶基质,研制紫杉醇纳米脂质体凝胶剂,采用正交试验探索最佳工艺。用粒径测定仪测定脂质体的粒径及其粒径分布,低速-超速相结合法测定包封率,透析膜扩散法进行体外释放试验,以离体小鼠皮结合改良Franz扩散装置考察其体外透皮特性。结果紫杉醇纳米脂质体的最佳工艺:卵磷脂的含量为2%,药物与磷脂质量比为1∶30,磷脂与胆固醇的质量比为10∶1。测得的粒径为81.8 nm;粒径分布系数为0.180;平均包封率73.2%。纳米脂质体凝胶剂72 h累积释放百分率为79.04%;48 h的单位面积累积渗透量为429.68μg·cm?2。结论该制剂制备工艺简单,易于涂布,具有较高的包封率,粒径较小且分布均匀,体外释放缓慢。纳米脂质体能促进脂溶性药物紫杉醇透过皮肤。     

N-三甲基壳聚糖包覆司帕沙星纳米脂质体原位凝胶的研制及体外释药研究

摘 要 目的：制备眼用N-三甲基壳聚糖（TMC）包覆的司帕沙星（SL）纳米脂质体原位凝胶（ISG）,并考察其体外释放度。方法: 采用pH梯度法制备SL脂质体,经高压均质至纳米级,用TMC包衣。以胶凝温度为指标,优选ISG基质泊洛沙姆407的最佳浓度,采用冷法制备TMC包覆SL纳米脂质体ISG。对TMC包覆SL纳米脂质体ISG中脂质体的形态、粒径、Zeta电位及包封率进行考察;以TMC包覆SL纳米脂质体为对照,采用无膜溶出模型考察其体外释药特性。结果: 泊洛沙姆407的最佳浓度为25%,在人工泪液中的胶凝温度为23.6 ℃,稀释后的胶凝温度为33.5 ℃。TMC包覆SL纳米脂质体ISG中脂质体形态圆整,平均粒径为（96.8±1.5）nm,Zeta电位为（46.2±1.4）mV,包封率为（76.6±2.4）%,与TMC包覆SL纳米脂质体相比无明显变化。TMC包覆SL纳米脂质体ISG药物释放和凝胶溶蚀均为符合零级动力学特征,且与TMC包覆SL纳米脂质体相比,缓释性更为显著。结论:TMC包覆SL纳米脂质体ISG胶凝温度理想,并可延缓药物释放。     

HPLC 法测定冰片-葛根素脂质体中葛根素的含量和包封率

目的：建立冰片-葛根素脂质体中葛根素含量及包封率测定方法.方法：采用薄膜分散法制备冰片-葛根素脂质体,葡聚糖凝胶柱层析法分离脂质体和游离药物,采用高效液相色谱法测定脂质体中葛根素的含量和包封率.结果：葛根素在8～160 μg·ml^-1范围内线性关系良好（r=0.999 8） ;柱层析法可有效分离药物,分离游离药物的柱回收率为99.32%（RSD=1.16%,n=9）,加样回收率为98.56%（RSD=1.23%,n=9）.3批样品的平均包封率为62.35%,65.41%,63.18%（n=3）.结论：该方法准确、灵敏,可用于冰片-葛根素脂质体中葛根素含量及包封率的测定.     

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.