水飞蓟素缓释滴丸的研制及其体外释放特性

目的:研究水飞蓟素缓释滴丸的处方和工艺,并对其体外释放特性进行了评价.方法:采用联合载体材料即聚乙二醇6000和泊洛沙姆188为速释性固体分散体载体材料,硬脂酸为缓释性骨架材料;熔融法制备水飞蓟素缓释滴丸,考察了滴丸成型的影响因素;并与市售片剂进行了释放度比较.结果:选择处方组成为水飞蓟素:聚乙二醇6000:泊洛沙姆188:硬脂酸(1:2:1:1.5);滴头直径为2.3 mm/4.1 mm,滴距为6 cm,滴速为40滴·min-1;该缓释滴丸10 h的最大累积溶出百分率可达92.5%.结论:所制得水飞蓟素缓释滴丸具有良好的缓释效果,为研发水飞蓟素新制剂提供参考.     

羟基喜树碱纳米脂质载体的制备及体外释放

采用“熔融乳化-高压均质法”制备以PEG40硬脂酸酯、PEG100硬脂酸酯修饰的纳米脂质载体PEG40-NLC和PEG100-NLC，并考察释放装置、NLC中脂质材料用量及释放介质流速对体外释放的影响。结果表明，PEG40-NLC和PEG100-NLC在桨-反向动态透析法和流通池-动态透析法中的释放曲线相似，而在转篮-动态透析法中的释放曲线与前二种装置的释放曲线均有显著性差异。随着NLC脂质材料用量增大，释放过程中药物扩散作用增强。对流通池法，释放介质流速增大，药物的释放加快。     

离子载体A23187介导pH梯度法制备重酒石酸长春瑞滨长循环脂质体

目的:采用A23187制备重酒石酸长春瑞滨长循环脂质体,优化了处方工艺,并考察了含量、包封率、药脂比和体外释放等检测指标。方法:采用A23187介导的pH梯度法制备了重酒石酸长春瑞滨脂质体;用HPLC法检测了脂质体中重酒石酸长春瑞滨的含量和脂质(HSPC)的含量,考察了药脂比;采用阳离子交换树脂分离脂质体和游离药物,HPLC法检测包封率;以4 mmol.L-1NH4Cl-PBS(pH 7.4)为体外释放介质考察了脂质体的体外释放行为。结果:重酒石酸长春瑞滨脂质体包封率为96.1%,药脂比为1∶5(w/w);高药脂比有利于延长药物体外释放的时间。结论:采用A23187介导的pH梯度法制备重酒石酸长春瑞滨脂质体工艺可行、载药量大、包封率高;所建立体外释放的检测方法快速、准确。     

水飞蓟素混悬剂的制备及稳定性和溶出度考察

目的:制备和初步筛选水飞蓟素混悬剂并对其物理稳定性和溶出度进行评价。方法:采用研磨法制备水飞蓟素混悬剂,并考察了处方因素对混悬剂稳定性以及释放度等的影响。结果:当水飞蓟素混悬剂中甘油用量为4%、羧甲基纤维素钠为1%和聚乙烯吡咯烷酮为12%时,沉降容积比、黏度和再分散性分别为90%,48mPa·s和100%。甘油和聚乙烯吡咯烷的加入使水飞蓟素在2min内累积释放量迅速达到20%以上。结论:初步确立水飞蓟素混悬剂的处方,其物理稳定性良好,且体外释放与同类水飞蓟素制剂比较有明显提高。     

棓丙酯脂质体的制备与表征

目的制备棓丙酯脂质体,并对其进行理化性质的表征和释放度的评价。方法采用薄膜分散法制备棓丙酯脂质体,超滤离心法测定脂质体的包封率,正交设计优化处方,并对其包封率、粒径、Zeta电位、形态及体外释放行为进行综合评价。结果正交设计优化最终处方为磷脂浓度5 mg.mL-1、药脂比1∶5、磷脂胆固醇比5∶1、水化介质离子强度20 mmol.mL-1,所得脂质体包封率为89.6%、粒径为181.3 nm、Zeta电位为-21.8 mV、4 h体外释放达到80%。结论制备的棓丙酯脂质体包封率高,粒径小而均一,体外释放完全。     

替硝唑原位固化缓释凝胶的处方研究

目的:应用Box-Behnken法设计并优化替硝唑原位固化缓释凝胶处方.方法:通过体外释放度的单因素影响试验确定考察因素与水平,以凝胶粘度、遇水固化时间、释放时间为响应变量,应用Box-Behnken法进行处方筛选与优化.结果:优化处方为35.3%(w/w)单甲氧基聚乙二醇-聚乳酸(mPEG-PDLLA 10/90),5.9% (w/w)替硝唑和58.8% (w/w)N-甲基-2-吡咯烷酮(NMP).该凝胶体外释放时间达192 h,无突释现象.结论:通过Box-Behnken法成功实现了替硝唑原位固化缓释凝胶的处方筛选.     

鬼臼毒素MPEG修饰脂质体的制备及体外释放的研究

目的:制备鬼臼毒素(PPT)MPEG修饰脂质体(PPT-MPL),以及考察PPT-MPL体外释放行为。方法:合成甲氧基聚乙二醇磷脂酰乙醇胺(MPEG-PE),并用薄膜分散法制备脂质体;以包封率为指标,运用正交试验法设计优化脂质体处方和工艺,采用改进的超滤法测定脂质体的包封率,以及透析法研究体外释放行为。结果:优化后的PPT-MPL平均粒径为(106.20±4.10)nm,包封率为(83.30±2.50)%;加入血浆后PPT-MPL体外释放速率比普通脂质体慢(P<0.05)。结论:该法制备PPT-MPEG修饰脂质体,具有粒径小、包封率高以及明显的缓释效果。     

右旋布洛芬缓释栓的研制

目的筛选右旋布洛芬缓释栓的最佳处方。方法用HPLC法测定右旋布洛芬缓释栓中右旋布洛芬的含量,采用正交设计,考察不同处方在1,3,6和8h的体外累积释放度,根据测得的数据设计最佳处方。结果在pH7.2的磷酸盐缓冲液中,采用转篮法,转速为50r.min-1条件下,最佳处方组成:以PEG4000为基质,HPMCK4M用量为8.0%,硬脂酸用量为1.0%。结论该处方设计合理,制剂制备工艺可行。     

甘草次酸修饰多西紫杉醇脂质体的制备和体外抑瘤效果

目的:制备甘草次酸(GA)修饰的多西紫杉醇脂质体,并初步考察其体外抗肿瘤效果.方法:化学合成甘珀酸十八醇酯(18-GA-Suc)作为修饰材料,采用薄膜分散法制备甘草次酸修饰的多西紫杉醇脂质体,考察影响脂质体包封率的因素.采用MTT法评价脂质体对HepG2细胞的体外抑瘤效果.结果:18-GA-Suc修饰的DX脂质体的体外抑瘤效果强于未修饰的DX脂质体,并且抑瘤效果随着载体中18-GA-Suc的增加而增强.结论:甘草次酸修饰的脂质体有望成为新型肝靶向的抗肿瘤载体.     

奥沙利铂聚乙二醇修饰脂质体的制备及其大鼠体内的药动学

采用逆相蒸发-挤出法制备奥沙利铂聚乙二醇(PEG)修饰脂质体,处方中蛋黄卵磷脂E80-胆固醇-聚乙二醇修饰二硬脂酰磷脂酰乙醇胺(PEG 2000-DSPE)重量比为100∶25∶34,药脂比为1∶10.所得制品平均粒径为140 nm,包封率97.5％.采用HPLC法测定大鼠血浆中的奥沙利铂,考察奥沙利铂PEG修饰脂质体静注给予大鼠的药动学情况,并与奥沙利铂溶液相比较.结果显示,奥沙利铂PEG修饰脂质体组的cmax和AUC均显著大于溶液组(P＜0.05);平均滞留时间(MRT)比溶液组延长了约20倍.说明奥沙利铂PEG修饰脂质体能延长药物在大鼠体内的循环时间.     

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.