球面对称设计优化胸腺五肽三甲基壳聚糖纳米粒的制备条件

目的探讨以三甲基壳聚糖为材料制备胸腺五肽纳米粒的制备条件。方法离子胶凝法制备胸腺五肽三甲基壳聚糖纳米粒(Tp5-TMC-NP),用球面对称设计优化制备条件,以粒径和包封率为评价指标,考查TMC浓度(X1)、海藻酸钠浓度(X2)、Tp5加入量(X3)三个指标对制备条件的影响,将实验结果用数学方法处理并进行方程模型拟合,根据拟合方程及由此绘制的反应曲面图(Response Surface Plot)考察指标的最优值和各因素相对应的最佳取值范围。结果以优化条件制得纳米粒粒径110.6 nm,药物包封率78.8%。结论制备方法简便,具有工业化生产的可行性。     

球面对称设计优化胸腺五肽三甲基壳聚糖纳米粒的制备条件

目的探讨以三甲基壳聚糖为材料制备胸腺五肽纳米粒的制备条件。方法离子胶凝法制备胸腺五肽三甲基壳聚糖纳米粒(Tp5-TMC-NP),用球面对称设计优化制备条件,以粒径和包封率为评价指标,考查TMC浓度(X₁)、海藻酸钠浓度(X₂)、Tp5加入量(X₃)三个指标对制备条件的影响,将实验结果用数学方法处理并进行方程模型拟合,根据拟合方程及由此绘制的反应曲面图(Response Surface Plot)考察指标的最优值和各因素相对应的最佳取值范围。结果以优化条件制得纳米粒粒径110.6 nm,药物包封率78.8%。结论制备方法简便,具有工业化生产的可行性。     

口服胸腺五肽乳酸-羟基乙酸共聚物纳米粒的制备及物理性质考察

目的制备供口服给药的胸腺五肽乳酸-羟基乙酸共聚物(thymopentin-poly lactic-co-glycolicacid;TP5-PLGA)纳米粒,并对纳米粒的物理性质进行考察。方法用复乳-溶剂挥发法制备TP5-PLGA纳米粒,以包封率为评价指标,用L16(45)正交设计优选纳米粒制备的处方工艺条件,用HPLC法测定胸腺五肽的含量,用激光粒度仪测定纳米粒的粒径,用透射电镜观察纳米粒的形态,用动态透析法考察纳米粒的体外释药特征。结果正交设计确定纳米粒制备的最优处方工艺条件为胸腺五肽质量浓度50 g.L-1,载体材料PLGA质量浓度100 g.L-1,乳化剂PVA质量浓度20 g.L-1;优化处方与工艺制备的纳米粒为规整的圆球形,平均粒径为(150.3±9.6)nm,载药量与包封率分别为(2.403±0.066)%与(28.12±0.60)%;体外释药结果表明,前5 h药物释放(31.27±1.5)%,存在一定突释,4 d累积释药量为(43.60±2.3)%。结论以乳酸-羟基乙酸共聚物为载体材料制备胸腺五肽纳米粒工艺简便,制剂具有良好的物理性质和体外释药特征。     

阿昔洛韦眼用壳聚糖纳米粒的制备及家兔生物利用度研究

目的:应用离子交联法制备阿昔洛韦壳聚糖纳米粒,考察其体外性质及其经家兔眼部给药后的生物利用度.方法:壳聚糖与三聚磷酸钠通过离子交联作用制备纳米粒,考察了纳米粒的粒径、Zeta电位、包封率以及体外释放性质,通过家兔眼部结膜囊内给药,考察眼房水中药物浓度的变化,并与市售阿昔洛韦滴眼液相比较.结果:阿昔洛韦壳聚糖纳米粒的平均粒径为235 nm,多分散系数为0.256,Zeta电位为43.9 mV;平均包封率为15.6%,平均载药量为1.9%;家兔眼部给药后,AUC0→6 h达到3.69μg·h-1·mL-1,是市售制剂的2.4倍.结论:实验初步证实制备的壳聚糖纳米粒可以促进阿昔洛韦的眼部吸收.     

咪喹莫特固体脂质纳米粒包封率的测定

目的:建立咪喹莫特固体脂质纳米粒包封率的测定方法。方法:采用热乳匀法制备咪喹莫特固体脂质纳米粒。用葡聚糖凝胶柱色谱法分离含药固体脂质纳米粒与游离药物,以蒸馏水和1．0×10-3mol·L-1盐酸溶液为洗脱液,用HPLC法测定游离药物量。结果:凝胶柱色谱法能够将包封药物和游离药物分开。游离咪喹莫特在0．335-2．69μg·ml-1浓度范围内,线性关系良好(r=0．999 9)。游离药物柱回收率为98．6％,柱的加样回收率为97．7％。样品的平均包封率为(51．43±0．88)％。结论:该方法操作简便,结果准确,可用于咪喹莫特固体脂质纳米粒包封率测定。     

盐酸吉西他滨壳聚糖纳米粒的制备及其体外释药特性研究

目的:优化盐酸吉西他滨壳聚糖纳米粒的制备参数,考察纳米粒体外释药特性。方法:以壳聚糖为辅料,采用离子交联法制备盐酸吉西他滨壳聚糖纳米粒,以包封率、载药量、粒径为参考指标设计试验,确定优化制备参数,以透射电镜观察其表观特征,考察纳米粒体外释药程度。结果:以优化参数制备的盐酸吉西他滨壳聚糖纳米粒包封率为(78.93±1.52)%,载药量为(11.71±0.88)%,纳米粒的平均粒径为(169±24)nm,体外释放试验表明纳米粒中盐酸吉西他滨的释放过程符合Higuchi方程。结论:盐酸吉西他滨可以通过离子交联法制备壳聚糖纳米粒,其粒径、包封率、载药量可控,具有缓释效果。     

雌二醇鼻用壳聚糖纳米粒的制备及体外性质的考察

目的 研究雌二醇壳聚糖纳米粒的理化性质及鼻黏膜吸收动力学.方法 以三聚磷酸钠(TPP)为交联剂,用生物降解聚合物材料壳聚糖(CS)制成纳米粒,通过离子凝胶化法制备雌二醇(E2)壳聚糖纳米粒,分别用动态光散射法仪测定了纳米粒的粒径,高速离心法测定其包封率,透析袋法对其体外释放过程进行了研究,采用大鼠在体灌流模型,考察了质量浓度分别为3.86、7.20、24.75、32.74、51.62 mg·L-1的雌二醇壳聚糖纳米粒的鼻黏膜吸收动力学.结果 当m(CS):m(TPP)在3:1～7:1之间时,可以形成壳聚糖纳米粒,5:1时得到得纳米粒最佳,平均粒径为(279.1±7.2)nm.随着E2质量浓度的增加,包封率有降低的趋势;E2在前2 h内发生突释现象,12 h释放量达80%以上.在循环液体积为5 mL、流速为2.5 mL·min-1下,不同质量浓度的雌二醇壳聚糖纳米粒鼻黏膜吸收速度常数不同,且随药液质量浓度的增加而增大.结论 通过离子凝胶化法制备的壳聚糖纳米粒外观呈半透明状,粒径较为均一,有一定的缓释效果,鼻黏膜吸收具有浓度依赖性,一定质量浓度条件下的吸收动力学过程为符合零级动力学.     

壳聚糖负载肉桂挥发油纳米粒制备工艺响应面法优化及质量评价

目的:优化壳聚糖负载肉桂挥发油纳米粒的制备工艺和处方,并对其质量进行评价。方法:采用单因素考察壳聚糖纳米粒制备的处方和工艺,以粒径、包封率和载药量为评价指标,应用星点设计-响应面法优化负载肉桂挥发油的壳聚糖纳米颗粒的制备工艺,采用透射电镜观察肉桂挥发油壳聚糖纳米粒形态,并对其稳定性进行研究。结果:壳聚糖负载肉桂挥发油纳米粒优化后的工艺为壳聚糖浓度0.2%,均质压力为500 bar(1 bar=0.1 MPa),循环次数为20次,TPP含量0.2 mg·mL^-1,在该条件下平均包封率为(83.37±0.40)%、平均载药量为(26.42±0.65)%、平均粒径为(248.5±12.2) nm, Zeta电位为(52.3±1.1) mV。透射电镜结果显示其呈粒径均匀的类球形,且肉桂油外包裹着一层壳聚糖。稳定性结果显示壳聚糖负载肉桂挥发油纳米粒混悬液在低温条件下贮存最佳。结论:负载肉桂挥发油壳聚糖纳米粒,制备工艺简单,可重复性较好,物理稳定性较好。     

乙酰半胱氨酸纳米粒的制备及体外释放研究

目的制备乙酰半胱氨酸纳米粒,并对其进行体外释放的研究。方法溶剂扩散法制备乙酰半胱氨酸纳米粒,单因素考察了壳聚糖浓度、油相中乙醇浓度、油水相比例对乙酰半胱氨酸纳米粒形态、大小、包封率的影响,通过透析袋法研究乙酰半胱氨酸纳米粒体外释药过程。结果经筛选得到形成纳米粒的最佳工艺为壳聚糖浓度2mg.min-1、乙醇浓度25%、油水相比为10∶1。该工艺制备纳米粒大小圆整,粒径为163±12.8nm,包封率达81%。体外释放结果表明,乙酰半胱氨酸纳米粒具有一定的缓释作用,药物在24h累积释放74.5%。结论溶剂扩散法制备乙酰半胱氨酸纳米粒方法简便、药物包封率高,该纳米粒是一种比较理想的乙酰半胱氨酸新剂型。     

N-琥珀酰壳聚糖纳米粒的制备及体外评价

目的制备N-琥珀酰壳聚糖纳米粒并对其进行体外评价。方法采用乳化溶剂挥发法制备N-琥珀酰壳聚糖纳米粒;以包封率、载药量及粒径为指标,采用正交设计法对处方进行优化;考察其理化特征及体外释药行为。结果纳米粒包封率及载药量分别为62.36%和18.98%,平均粒径及zeta电位分别为(206.6±64.7)nm和(-27.2±0.2)mV;1 h药物释放达到45%,随后药物的释药行为是一个缓释过程。结论作者采用乳化溶剂挥发法成功制得N-琥珀酰壳聚糖纳米粒。该方法制得纳米粒包封率较高,制备工艺简单。     

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.