高效液相色谱-串联质谱法测定牛奶中6种青霉素类药物的残留量

目的 建立一种高效液相串联质谱法,快速测定牛奶中6种青霉素类抗生素的残留鼍.方法 样品经乙腈沉淀蛋白,正己烷脱脂,氮吹浓缩,经高效液相色谱C18柱分离,选用含0.1%甲酸的水溶液和0.1%甲酸的乙腈溶液作流动相,在22 min内梯度洗脱将6种青霉素类抗生素得以分离.结果 方法 检出限为青霉素G 0.5ng/ml、青霉素V 1.0 ng/ml、苯唑西林1.0ng/ml、氯唑西林2.0ng/ml、阿莫西林2.0 ng/ml以及双氯西林1.0 ng/ml,在0.5～20 ng/ml线性范围内,相关系数r均大于0.990,平均回收率均大于80%.结论 该方法 前处理过程快速,结果 准确可靠,灵敏度高.     

HPLC法测定6-氨基青霉烷酸中苯乙酸和青霉素G含量

目的 建立6-氨基青霉烷酸中苯乙酸和青霉素G含量的测定方法.方法 用苯基柱;甲醇pH3.5磷酸盐缓冲溶液水(301060)为流动相;检测波长220nm;流速1.5ml/min;进样量10μl.结果 6-氨基青霉烷酸、苯乙酸峰和青霉素G峰完全分离;样品连续测定6次,苯乙酸和青霉素G的RSD分别为0.89%和0.92%;苯乙酸在0.005～0.040 mg/ml范围内、青霉素G在0.011～0.086 mg/ml 范围内呈良好的线性关系(相关系数均大于0.9999);苯乙酸和青霉素G平均回收率分别为99.12%(RSD=2.8%)和100.05%(RSD=1.O%);检测限分别为3.36×10-5和4.61×10-5mg/ml;定量限分别为1.135×10-4和1.076×10-5mg/ml.结论 该方法专属性好、准确度高,可用于6-氨基青霉烷酸中杂质苯乙酸和青霉素G的含量测定.     

苯唑青霉素和庆大霉素对肠球菌的协同作同

本文测定了从病人分离得到的34株肠球菌对苯唑青霉素和庆大霉素(单独及联合)的敏感度,以探讨两种抗菌素对肠球菌有无协同作用。苯唑青霉素对上述肠球菌的最低杀菌浓度为16～250微克/毫升(中数32微克/毫升),庆大霉素为12～48微克/毫升(中数24微克/毫升)。当苯唑青霉素与不同浓度(12、6、3、和1.5微     

反相HPLC法测定甲苯磺酸舒他西林中舒他西林及其杂质氨苄青霉素、舒巴克坦的含量

本文建立了用对氨基苯乙酮为内标测定甲苯磺酸舒他西林中舒他西林及其杂质氨苄青霉素、舒巴克坦含量的HPLC法。使用Spherisorb C_(18)色谱柱(4.6ID×250mm,5μm);0.05%氢氧化四丁基铵的磷酸盐缓冲液(pH3.0~3.1):甲醇:乙腈(64:10:26)为流动相;在检测波长215nm,柱温40℃,进行含量测定。舒他西林在0.4~1.2mg/ml、氨苄青霉素在0.03~0.12mg/ml、舒巴克坦在0.01~0.05mg/ml的浓度范围内均有良好的线性关系。最低检出量分别为33ng、18ng、46ng。     

HPLC法同时测定青霉素钠和地塞米松磷酸钠的含量

目的寻找简便高效的液相色谱法同时测定青霉素钠与地塞米松磷酸钠的浓度。方法采用外标法进行含量测定,色谱柱为SymmetryC18柱(4.6mm×150mm,5.0μm);流动相为0.02mol/L磷酸二氢钾溶液(用磷酸调pH至3.1)—甲醇(38∶62);流速1ml/min;检测波长242nm。结果该方法下青霉素钠与地塞米松磷酸钠线性范围分别为0.1842～12.2800mg/ml,1.8～120.0μg/ml;平均回收率分别为98.8%,99.2%;标准曲线相关性良好。结论本法操作简便,结果准确,适合实际应用。     

特拉唑嗪胶囊的药物动力学及相对生物利用度研究

目的:建立人血浆中特拉唑嗪浓度的HPLC荧光测定方法,研究特拉唑嗪在人体中的药物动力学行为。方法:血浆样品经碱化后,用乙酸乙酯和苯(1:4)提取,色谱柱为 Hypersil-ODS柱,流动相为0.05 mol/L磷酸二氢钾-乙腈-四氢呋喃(70:29.2:0.8),荧光检测器的激发波长为250 nm,发射波长为 370 nm。测定了20名受试者单剂量口眼特拉唑嗪胶囊和市售片剂后的血药浓度。结果:特拉唑嗪浓度在1.5～150.0 ng/ml范围内,线性关系良好(r=0.9994),最低检测限达 1ng/ml,绝对回收率大于 70％,符合生物样品分析要求。受试者口服特拉唑嗪胶囊和片剂 2 mg后,估算的半衰期分别为 10.90±2.24 h和 11.58±2.47 h,达峰时间分别为 1.6±0.6 h和 1.3±0.5 h,峰浓度分别为 36.97±3.53 ng/ml和 38.95±8.31 ng/ml,特拉唑嗪胶囊剂的相对生物利用度为98.0％。结论:特拉唑嗪胶囊剂与市售特拉唑嗪片剂生物等效。     

耐甲氧西林金黄色葡萄球菌的苯唑西林、头孢西丁最低抑菌浓度与青霉素结合蛋白2a的相关性

为分析金黄色葡萄球菌(S·aureus,SA)的青霉素结合蛋白2a(PBP2a)的产生与头孢西丁、苯唑西林最低抑菌浓度(MIC)相关性,收集102株临床分离株,采用MIC法分别检测SA对头孢西丁、苯唑西林的耐药性,并与耐甲氧西林SA(MRSA)胶乳凝集法对比分析。结果表明,头孢西丁MIC≥32μg/ml71例(69·6%),其中乳胶凝集试验阳性70例(98·6%);苯唑西林MIC≥4μg/ml80例(78·4%),乳胶凝集试验阳性70例(87·5%)。头孢西丁阳性的PBP2a检出率明显高于苯唑西林(98·6%比87·5%,P<0·05)。结论:头孢西丁MIC≥32μg/ml或产生PBP2a的SA均能正确地表达为MRSA;苯唑西林MIC≥4μg/ml解释标准对SA评价MRSA正确性较低。     

特拉唑嗪胶囊的药物动力学及相对生物利用度研究

目的:建立人血浆中特拉唑嗪浓度的HPLC荧光测定方法,研究特拉唑嗪在人体中的药物动力学行为。方法:血浆样品经碱化后,用乙酸乙酯和苯(1:4)提取,色谱柱为 Hypersil-ODS柱,流动相为0.05 mol/L磷酸二氢钾-乙腈-四氢呋喃(70:29.2:0.8),荧光检测器的激发波长为250 nm,发射波长为 370 nm。测定了20名受试者单剂量口眼特拉唑嗪胶囊和市售片剂后的血药浓度。结果:特拉唑嗪浓度在1.5～150.0 ng/ml范围内,线性关系良好(r=0.9994),最低检测限达 1ng/ml,绝对回收率大于 70％,符合生物样品分析要求。受试者口服特拉唑嗪胶囊和片剂 2 mg后,估算的半衰期分别为 10.90±2.24 h和 11.58±2.47 h,达峰时间分别为 1.6±0.6 h和 1.3±0.5 h,峰浓度分别为 36.97±3.53 ng/ml和 38.95±8.31 ng/ml,特拉唑嗪胶囊剂的相对生物利用度为98.0％。结论:特拉唑嗪胶囊剂与市售特拉唑嗪片剂生物等效。     

青霉素酰化酶电极

用海藻酸钠-氯化钙包埋法制备青霉素酰化酶电极,电极涂液中海藻酸钠浓度为1％,酶量大于15U/100mg较好。经聚乙烯亚胺处理的电极的抗磷酸盐性能良好,测试在pH 7.05缓冲液中进行,加样搅拌平衡后,取停止搅拌5min后的pH读数,△pH-青霉素G浓度的线性范围为0～1.88mg/ml。温度和pH对pH响应值均有影响。     

旋光法测定苯唑青霉素钠含量

苯唑青霉素钠的含量测定中国药典采用双相中和法,该法虽然结果比较准确,但测定条件要求高,操作比较费时,不适应药厂、医院对其产品质量控制和快速分析的需要。根据苯唑青霉素钠具有旋光性的特点([α]~(20)D 195°～214°),笔者直接应用旋光法测定其含量,并同药典对照,结果满意。鉴于尚无本法测定苯唑青霉素钠     

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.

---

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.