盐酸利多卡因脂质体凝胶剂的体外透皮扩散研究

目的 对盐酸利多卡因(lidocaine hydrochloricde,LDH)脂质体凝胶剂体外透皮量、皮肤层滞留量进行评价.方法 超声法制备LDH脂质体,再用卡波普为基质制成凝胶剂;以体外经皮渗透释药法,比较LDH脂质体凝胶剂及LDH凝胶剂中的经皮渗透规律.结果 平均包封率为(83.4±1.81)%;LDH 凝胶剂的渗透符合Higuchi方程,其中脂质体凝胶剂24h内药物渗透速率为770.32μ g·h-1,明显高于游离药物凝胶渗透率280.01μg·h-1.结论 载药脂质体凝胶剂可显著促进药物经皮吸收,为经皮吸收药物的理想载体.     

丁卡因脂质体凝胶剂的研究

目的:研制丁卡因脂质体凝胶剂,为临床新制剂的开发提供参考。方法:以逆相蒸发—超声法等制备丁卡因脂质体凝胶剂;并采用改良Franz扩散池体外经皮渗透实验技术,对丁卡因脂质体凝胶剂及其普通凝胶剂的经皮渗透作用进行了比较。结果:丁卡因脂质体平均粒径为105.5 nm,平均包封率为 63.8％;体外透皮实验中,12 h累积透皮吸收百分率(Q％)为34.6％,明显高于普通凝胶制剂(17.7％);皮内药物滞留百分率(Q_滞％)分别为24.6％,明显高于普通凝胶制剂(0.65％)。结论:丁卡因脂质体凝胶剂有望成为适于临床给药的一种新剂型。     

博莱霉素脂质体凝胶的制备和体外透皮性比较

目的：研制博莱霉素（BLM）脂质体凝胶,并对其皮肤靶向性进行体外评价。方法：采用逆相蒸发-冻融法制备BLM脂质体,再用卡渡姆940为基质制成BLM脂质体凝胶;以离心法测定BLM脂质体的包封率;以体外透皮渗透释药法,比较BLM脂质体凝胶与BLM普通凝胶的透过作用。结果：BLM脂质体平均粒径为（885．20±12．08）nm,平均包封率为（66．80±1．38）％。在24h内,BLM脂质体凝胶累积透过量（Q）及稳态透皮速率（J）与BLM普通脂质体相比,均明显提高,而在皮肤中的滞留药量也显著提高（P〈0．05）。结论：BLM脂质体凝胶在体外可显著增加BLM的透皮吸收,增加皮肤中的滞留量,值得进一步研究。     

酮洛芬脂质体凝胶的研制及体外经皮渗透动力学考察

目的:研制酮洛芬(KPF)脂质体凝胶,并进行体外经皮渗透动力学研究。方法:通过均匀实验设计筛选KPF脂质体的最佳处方,采用薄膜分散法制备脂质体,再以泊洛沙姆-407为基质制成脂质体凝胶;以影响因素试验考察该制剂的稳定性,并用Franz扩散池研究KPF脂质体凝胶与KPF普通凝胶的经皮渗透规律。结果:KPF脂质体平均粒径为(886.2±12.08) nm,Zeta电位为(-15.05±2.36)mV,平均包封率为(76.13±1.27)%(n=3);KPF脂质体凝胶为类白色细腻粘稠胶体,对试验光照及温度条件稳定。体外透皮试验表明脂质体能促进药物的透皮吸收,脂质体凝胶在皮肤中的蓄积量为普通凝胶的2倍。结论:KPF脂质体凝胶制备工艺可行,质量稳定,检测方法可靠,能促进药物透皮渗透,值得进一步研究。     

盐酸多西环素脂质体凝胶剂的制备与评价

以薄膜-振荡分散法制备盐酸多西环素脂质体，再以卡波姆为基质制备脂质体凝胶剂。比较了制品及普通凝胶剂对离体鼠皮的经皮渗透作用。结果表明，制品平均粒径为200～300nm，包封率为80．1％。体外透皮实验中，脂质体凝胶剂24h的药物浓度为156，7μg／ml，明显高于普通凝胶剂（83．3μg／m1）。     

复方克林霉素脂质体凝胶的制备及体外透皮释药研究

目的制备复方克林霉素脂质体凝胶并考察其粒径分布、包封率及体外透皮特性。方法采用薄膜分散法制备复方克林霉素脂质体,利用透射电镜观察其形态,用激光纳米粒度仪测定其粒径大小及分布,用HPLC法测定其包封率。将脂质体进一步制成凝胶剂后,考察其体外透皮情况。结果复方克林霉素脂质体的粒径在240nm左右,分布均匀,平均包封率为51.24%;脂质体中的克林霉素能缓慢透过大鼠皮肤,缓释效果明显。结论该制剂制备工艺简单,性质稳定,药物包封率较高,定量测定方法简便、准确;药物透皮速率缓慢,释药稳定。     

羟基喜树碱脂质体的制备及质量评价研究

目的:制备羟基喜树碱(HCPT)脂质体,并对其质量进行评价.方法:采用薄膜分散-高压乳匀法制备羟基喜树碱脂质体;用激光粒度分析仪测定其Zeta电位、粒径大小;考察其在0.9%NaCl溶液、水、5%葡萄糖溶液中8 h的稳定性;用凝胶柱层析法考察包封率;采用薄膜透析法考察体外释药性质.结果:羟基喜树碱脂质体Zeta电位为(-33.1±1.3) mV,平均粒径(182.5±5.6) nm,8 h内在水、5%葡萄糖溶液中稳定性良好;包封率(91.2±1.2)%;体外释药曲线符合Higuchi方程Q=1.291 6t1/2 0.309 8,r=0.980 3.结论:本试验制备的羟基喜树碱脂质体稳定性好,大小均匀, 包封率高,并具有延缓药物释放的性质.     

塞来昔布脂质体凝胶的研制及其体外经皮渗透动力学考察

目的研制塞来昔布脂质体凝胶,并对其体外经皮渗透动力学进行考察。方法采用薄膜分散法制备塞来昔布脂质体,均匀设计筛选最佳处方及制备工艺,并以卡波姆940为基质制成脂质体凝胶;用Franz扩散池研究塞来昔布脂质体凝胶与塞来昔布普通凝胶的经皮渗透规律。结果塞来昔布脂质体凝胶的平均粒径为(369.5±10.8)nm,平均包封率为(81.6±2.2)%(n=3);体外透皮试验表明塞来昔布脂质体凝胶的累积透过量显著大于普通凝胶(P<0.05),药物透皮速率与皮肤蓄积量显著大于普通凝胶(P<0.01)。结论塞来昔布脂质体凝胶制备简单,能促进药物透皮吸收,值得进一步研究。     

丹皮酚脂质体凝胶剂的透皮作用机制考察

目的 研究丹皮酚脂质体凝胶的体外透皮扩散作用。方法 采用Franz扩散池,以大鼠皮肤进行体外经皮渗透试验,考察丹皮酚脂质体凝胶的经皮渗透行为及皮肤内药物滞留量。结果 制得的丹皮酚脂质体凝胶包封率为78.62%,平均粒径为127 nm。体外经皮渗透试验表明,与丹皮酚凝胶相比,丹皮酚脂质体凝胶透皮速率较慢,但皮肤中药物滞留量明显增加。结论 丹皮酚脂质体凝胶制备工艺可行,其体外释放有明显缓释特征,有望成为丹皮酚应用的新剂型。     

曲马多缓释多囊泡脂质体的制备和释放度影响因素研究

目的 制备包封率高和缓释作用好的PGE修饰的曲马多缓释缓释多囊泡脂质体,并与逆相蒸发法制备的曲马多普通脂质体比较其体外释药性能.方法 用复乳法制备曲马多缓释多囊泡脂质体;非火焰原子吸收分光光度法测定曲马多含量;磷脂酶试剂法测定脂质体中磷脂的浓度;测定包封率和体外释药性.结果 曲马多缓释多囊泡脂质体平均粒径为31.3μm,跨距为1.0;曲马多包封率可高达80%以上;曲马多缓释缓释多囊泡脂质体的体外释药符合一级释药规律,释药时间为72h,比逆相蒸发法制备的曲马多普通脂质体延长16.95（由原来为释药时间37.7h延长8.4倍推出）倍;经差示热分析发现辅助膜稳定剂有明显的膜稳定作用.结论 曲马多缓释多囊泡脂质体包封率高,并具有良好的缓释作用.     

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.