丹皮酚脂质体的制备及质量控制方法研究

目的:制备丹皮酚脂质体并对其进行质量控制方法研究。方法:采用正交试验优选处方,薄膜-超声法制备丹皮酚脂质体;观察脂质体的形态和粒径,并采用高效液相色谱法对丹皮酚进行含量测定。结果:优选的最佳处方为大豆卵磷脂与胆固醇用量比为4∶1,大豆卵磷脂与丹皮酚用量比为10∶1,维生素E用量为0.1%;制备的丹皮酚脂质体为粒径均一的圆球形结构,平均粒径为359.3nm,包封率为71.55%,渗漏率为1.64%。丹皮酚的检测浓度在8.32～49.92μg·mL-1范围内与峰面积积分值呈良好线性关系(r=0.9999)。结论:制备的丹皮酚脂质体包封率高、渗漏率低,为进一步制备丹皮酚脂质体凝胶奠定了基础。     

伊曲康唑脂质体的制备工艺研究

目的:优化伊曲康唑脂质体的制备处方和工艺.方法:采用正交设计法,以伊曲康唑脂质体冻干粉重建包封率、粒径分布、渗漏率3个指标综合评分.结果:伊曲康唑脂质体的最佳工艺处方为药物-脂材比1∶30,胆固醇-磷脂比1∶5.5,去氧胆酸钠-脂材比1∶7,甘露醇和乳糖的用量为处方总重的60%,水合介质为磷酸盐缓冲液(pH=6.0),采用薄膜水化超声-冷冻干燥工艺制备.结论:按最优处方制得的脂质体的外观比较圆整,包封率和粒径均较好.     

不同制备方法对硫酸多黏菌素E脂质体包封率的影响

目的筛选硫酸多黏菌素E脂质体2种制备方法的最优处方,选择适合的制备方法。方法薄膜分散-超声法、逆相蒸发法制备脂质体,HPLC测定硫酸多黏菌素E脂质体包封率,正交设计法优化脂质体处方。结果制得的脂质体形状均匀、粒径适宜,包封率较高。结论逆相蒸发法较薄膜分散-超声法更适合于硫酸多黏菌素E脂质体的制备。     

羟基喜树碱脂质体的制备与性质研究

目的：确定羟基喜树碱脂质体的制备工艺。方法：利用薄膜分散-超声法制备羟基喜树碱脂质体,并对制备得到的脂质体进行粒径、稳定性和体外释放的评价。结果：制备到得平均粒径为较小,并具有一定缓释效果的羟基喜树碱脂质体。结论：薄膜分散-超声法适用于制备粒径均一、包封率较高HCPT脂质体。     

苯丁酸氮芥脂质体的制备及处方因素考察

目的 制备苯丁酸氮芥脂质体并优化其处方。方法 薄膜超声分散法制备苯丁酸氮芥脂质体,采用微柱离心-HPLC法测定其包封率,以包封率为考察指标,研究膜材比、药脂比、水相介质pH值以及磷脂浓度等因素对脂质体包封率的影响;通过正交试验对处方进行优化,并进行质量评价。结果 苯丁酸氮芥脂质体优化后的制备处方为胆固醇与磷脂质量比1∶3、药脂比1∶10、水相介质pH值为7.4、磷脂浓度为0.3%。按该处方制得的苯丁酸氮芥脂质体包封率>87%,平均粒径为84.71 nm,PDI为0.167。结论 优选处方稳定可行,制备的苯丁酸氮芥脂质体包封率高、粒径小且均匀。     

Box-Behnken效应面法优化制备主动载药盐酸小檗碱脂质体

目的采用Box-Behnken效应面法筛选最佳处方,制备盐酸小檗碱脂质体。方法采用薄膜分散-p H梯度法制备脂质体,分别以磷脂与胆固醇质量比、脂药质量比、外水相p H值、孵化温度为考察对象,以包封率、粒径和载药量为评价指标,采用4因素3水平Box-Behnken效应面设计法筛选盐酸小檗碱脂质体的最佳处方。采用阳离子交换树脂微柱离心法测定包封率,动态激光散射法测定脂质体的粒径,并采用透射电镜观察制得的脂质体形态。结果最优处方工艺条件为磷脂与胆固醇质量比为3.38∶1,脂药质量比为22∶1,外水相p H为6.88,孵化温度为59℃。以最优处方制备的盐酸小檗碱脂质体平均粒径、包封率、载药量与预测值偏差较小。结论采用Box-Behnken效应面法优化盐酸小檗碱脂质体工艺处方是可行的。     

洛伐他汀脂质体的制备及表征

目的：研制洛伐他汀脂质体,考察其制备的影响因素,优化处方工艺,并对其特性进行表征。方法：采用薄膜分散法制备洛伐他汀脂质体,以包封率、粒径和Zeta电位为指标参数,考察表面活性剂、水合介质及药脂比对其制备的影响;并评价其理化性质及稳定性。结果：以脱氧胆酸钠-泊洛沙姆188（1∶2）为表面活性剂、去离子水为水合介质和药脂比为1∶40制备的洛伐他汀脂质体具有最佳的包封率（〉90%）、粒径（90～110 nm,分布系数为0.32）和Zeta电位（-35～-39 mV）;其外观圆整,内部具指纹状结构;在4℃下放置30 d,包封率、粒径及Zeta电位均无明显变化。结论：采用薄膜分散法制备的洛伐他汀脂质体具有良好的理化特性及稳定性。     

高压微射流优化盐酸多柔比星脂质体的制备及质量评价

在薄膜分散-超声法的基础上,采用高压微射流法制备粒径进一步降低且更稳定的空白脂质体,再以pH梯度法包载盐酸多柔比星.结果表明,空白脂质体的最佳制备条件为:大豆磷脂-胆固醇为4∶1 (w/w),高压微射流压力为25 000 psi,循环10次;载药脂质体的最佳载药条件为:药脂比1∶20,70℃温育60 min.所得优化脂质体平均粒径为(116.9±1.2) nm,包封率为(98.27±0.60)％,40 h药物累积释放率为67.9％.该脂质体在4℃避光密闭条件下放置14d,粒径无明显变化,包封率保持在90％以上.     

八聚精氨酸修饰的载紫杉醇脂质体的制备工艺研究

目的 研究八聚精氨酸(R8)修饰的载紫杉醇脂质体的制备工艺.方法 采用有机相反应法,将R8修饰到脂质体表面,并以薄膜分散-探头超声法制备载紫杉醇脂质体,以细胞摄取、粒径、PDI、包封率为主要指标对磷脂/胆固醇、药脂比、水化液种类、R8密度、DSPE-PEG2000密度进行筛选,进一步优化处方.结果 最优处方为磷脂-胆固醇2∶1、药脂比1∶40、水化液为PBS(pH6.5)、R8密度5％、DSPE-PEG2000密度3％,所制脂质体的粒径为156 ±2 nm,PDI＝ 0.25,包封率为80.87％±8.9％.结论 成功制备了八聚精氨酸(R8)修饰的载紫杉醇脂质体.     

替尼泊苷长循环阳离子脂质体的制备

目的优化薄膜分散法制备替尼泊苷长循环阳离子脂质体的最佳处方。方法薄膜分散法制备脂质体,以粒径和包封率为考察指标,用单因素考察和正交设计等方法优化脂质体的处方。结果优化后的最佳处方为:磷脂DSPC和PEG 5 000-DOTMA比为4∶1,药物和磷脂比为1∶4,磷脂与胆固醇比为2∶1,乳化剂为卵磷脂。优化的脂质体平均粒径为115.45nm,平均Zeta电位为25.54mV,平均包封率为91.32%,5±3℃放置180d和25±2℃放置30d各项指标变化不显著。结论制备的替尼泊苷长循环阳离子脂质体包封率高,粒径小,释放缓慢,稳定性和安全性好。     

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.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

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.