抗癫疒间肽纳米粒的制备及体外释药性能的研究

目的制备抗癫疒间肽纳米粒,并研究其体外释药性能。方法选用聚乙二醇-聚乳酸-聚乙醇酸嵌段共聚物为载体,采用复乳-溶剂挥发法制备抗癫疒间肽纳米粒,以包封率、载药量等指标优化制备工艺,并研究纳米粒体外释药性能。结果抗癫疒间肽纳米粒外观呈圆形或类圆形,平均粒径为(100.2±2.45)nm,包封率和载药量分别为(64.46±1.34)%和(4.73±0.32)%,体外释药呈现缓释和突释两个阶段,符合Weibull方程。结论建立的制备工艺简便可行,得到的抗癫疒间肽纳米粒包封率和载药量较高,粒径小,体外释药具有明显的缓释特征。     

5-氟尿嘧啶聚乙二醇-聚十六烷基氰丙烯酸酯纳米粒的制备

目的:以聚乙二醇-聚十六烷基氰丙烯酸酯(PEG-PHDCA)聚合物制备5-氟尿嘧啶(5-Fu)纳米粒,并对其进行体外释药研究.方法:采用溶剂扩散法制备5-Fu PEG-PHDCA纳米粒,在单因素基础上采用正交设计法优化得到最佳处方,并对5-Fu聚合物纳米粒的粒径、Zeta电位、载药量、包封率和体外释放进行了研究.结果:制得的5-Fu聚合物纳米粒的平均粒径为132 nm,Zeta电位为-(12±2)V,载药量为12.3%,包封率为48.8%.体外释放研究发现,5-Fu PEG-PHDCA纳米粒释药近似符合Higuchi释药模型:Q=0.564 4+8.386t1/2(r=0.996 0).结论:采用溶剂扩散法制备5-Fu聚合物纳米粒方法简单,重现性好,其体外释放显示出明显缓释作用.     

5-氟尿嘧啶共聚物纳米粒的制备及其药剂学性质

目的 以生物可降解材料Pluronic P105-PAGA共聚物制备5-氟尿嘧啶(5-FU)纳米粒,并考察纳米粒的药剂学特性.方法 采用透析法制备纳米粒,以包封率和载药量为指标,应用星点设计效应面优化法优化处方,并考察其表面特征、包封率、载药量、粒径、体外释放等性质.结果 5-FU-Pluronic P105-PAGA纳米粒为圆整的类球形实体粒子,平均粒径为175 nm,载药量为22.37%,包封率为95.26%,有突释现象,体外12 h累积释放率为80.4%.结论 所制纳米粒具有高包封率和载药量,粒径适宜,具有一定的缓控释作用.     

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。     

半乳糖化阿霉素白蛋白纳米粒的制备及其质量评价

目的:制备半乳糖化阿霉素白蛋白纳米粒,并考察了其形态、粒径、载药量、包封率和体外释药特性.方法:采用相分离法制备阿霉素白蛋白纳米粒,并在其表面偶联半乳糖苷,使之成为半乳糖化白蛋白纳米粒.激光扫描电子显微镜观察纳米粒的形态,马尔文激光粒度仪测定其粒径分布.采用紫外分光光度法测定纳米粒的载药量和包封率,并初步研究其体外释药特性.结果:电镜结果显示阿霉素纳米粒呈类球型,平均粒径为316.3 nm,纳米粒载药量为3.12%,包封率达91.82%,48 h体外累积释药率为55.71%.结论:本方法制备阿霉素纳米粒工艺简单且包封率较高.体外释药结果显示半乳糖化阿霉素白蛋白纳米粒具有明显的缓释作用.     

口服藻酸双酯钠纳米粒的制备、体外释药特性及其药效学研究

目的为了提高藻酸双酯钠(PSS)口服制剂的稳定性及其生物利用度,制备藻酸双酯钠的口服纳米粒(PSS-NP),并对其理化性质、体外释药特性及其药效学进行考察。方法采用改进的双乳化溶剂蒸发法(W1/O/W2)制备藻酸双酯钠纳米粒并设计正交试验筛选最优处方;透射电镜观察纳米粒形态;粒度及表面电位分析仪测量纳米粒的粒径及zeta电位;氧瓶燃烧法测定载药纳米粒的包封率与载药量;超速离心法考察载药纳米粒的体外释药特性;正常小鼠灌胃给药测定降血糖效果。结果与结论优化的口服藻酸双酯钠纳米粒为规则的圆球形,其粒径大小为181.8 nm,包封率为75.80%,载药量为10.83%,zeta电位为-17.3 mV;12 h内PSS-NP累积释药百分率为60.37%;PSS-NP对正常小鼠具有显著的降血糖效果。     

盐酸伊立替康纳米粒的制备及体外评价

目的:制备盐酸伊立替康纳米粒,并对其纳米粒形态、粒径、包封率和释放进行评价。方法:采用沉淀法制备盐酸伊立替康纳米粒,以包封率作为考察指标,筛选最优处方。用透射电镜观察纳米粒形态,激光粒径测定仪测定粒径,凝胶过滤法测定药物的包封率,透析法考察体外释药特质。结果:盐酸伊立替康纳米粒形态规整,几呈球形,强度径为(193.5±2.5)nm,载药量为26.35%,包封率为(98.00±0.01)%,体外24h的累积释放率为62.09%,比水溶液释放慢。结论:通过优化处方和工艺,制备出的盐酸伊立替康纳米粒粒径均匀,包封率较高,体外释药具有缓释特点。     

阿霉素壳寡糖纳米粒的制备及体外抗肿瘤研究

目的制备负载阿霉素的壳寡糖纳米粒,并研究其理化性质和体外抗肿瘤细胞毒性。方法采用离子凝胶法制备负载阿霉素的壳寡糖纳米粒;透射电镜观察纳米粒形态,激光粒度仪测定粒径和表面电位,紫外分光光度法测量包封率、载药量,考察载药纳米粒的体外释药特性;采用MTT法对载药壳寡糖纳米粒在体外乳腺癌细胞株MCF-7的细胞毒作用进行评价。结果制得的阿霉素壳寡糖纳米粒呈球形或类球形,形态较为完整,平均粒径为(136.77±1.21)nm,表面电位为(20.53±0.31)m V,包封率为(56.99±1.40)%,载药量为(15.49±0.38)%,168 h的累积释放率为72.15%;阿霉素和载药纳米粒对MCF-7细胞增殖的抑制作用存在明显的浓度和时间依赖性,且载药纳米粒对MCF-7细胞增殖的抑制作用随时间增加而逐渐强于游离阿霉素。结论此方法制备的阿霉素壳寡糖纳米粒粒径较小,药物释放具有明显的缓释作用,并具有较好的抗肿瘤作用。     

葛根素磷脂复合物纳米粒的制备及体外评价

目的制备葛根素磷脂复合物,以聚氰基丙烯酸正丁酯(PBCA)为载体材料,制备葛根素磷脂复合物纳米粒,并对其进行体外评价。方法采用界面缩合聚法制备纳米粒。以复合率、包封率和载药量为评价指标,通过单因素和正交试验法优选处方和工艺。结果葛根素磷脂复合物的最佳处方及工艺:反应溶剂为无水乙醇,葛根素与磷脂的投料比为1∶2;葛根素磷脂复合物纳米粒的最佳处方及工艺:pH=3.0、α-氰基丙烯酸正丁酯(α-BCA)的浓度为0.8%、V油相∶V水相=1∶60、葛根素磷脂复合物的投药量为1.0 mg。制备的纳米粒平均粒径为(115.1±3.45)nm、包封率为(90.03±1.80)%、载药量为(11.80±0.12)%。体外释药在24 h累积释放量约为80%。结论本研究所制备的葛根素磷脂复合物纳米粒包封率和载药量高、性质稳定、体外释药具有缓释行为。     

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.