6－脱氧土霉素磺基水杨酸盐的紫外分光光度测定

以紫外分光光度法测定６－脱氧土霉素磺基水杨酸盐，检测波长为３４９ｎｍ，平均回收率１００．２７％，ＲＳＤ０．１８９％。本法操作简便，结果准确。     

紫外分光光度法测定土霉素含量

根据土霉素在紫外区有吸收的特点,试用紫外分光光度法测定其含量,用于对购入的药品进行快速监测,结果较满意.现介绍如下.一、仪器与试药UV-120可见紫外分光光度计(日本岛津),1/万分析天平(上海天平仪器厂产),土霉素标准品864u/mg(中国药品生物制品检定所产),土霉素片(大连金铎制药厂),批号分别为:92060101,92070902,92020701,92027103.     

6—脱氧土霉素磺基水杨酸盐的紫外分光光度测定

以紫外分光光度法测定６－脱氧土霉素磺基水杨酸盐，检测波长为３４９ｎｍ，平均回收率１００．２７％，ＲＳＤ０．１８９％。本法操作简便，结果准确。     

土霉素片溶出度测定方法研究

目的:建立土霉素片溶出度的测定方法。方法:在检测波长271nm下用紫外分光光度法测定土霉素含量;以0.01mol·L-1盐酸溶液作溶剂,选用桨法测定土霉素片溶出度。结果:土霉素检测浓度线性范围为4～32IU·mL-(1r=0.9999)。平均回收率为100.1%(RSD=0.65%);45min时样品溶出度均在75%以上。结论:所建立方法可用于土霉素片溶出度测定。     

紫外分光光度法测定土霉素片中间体(颗粒)的含量

目的:改进土霉素中间体(颗粒)的检验方法,以提高产品质量的稳定性。方法:用紫外分光光度法替代光电比色法。结果:操作简便,结果准确。结论:此法优于原方法。     

高效毛细管电泳法分离土霉素及其相关物质的方法研究

目的：采用高效毛细管电泳法分离土霉素及其相关物质。方法：以含1mmol/L的EDTA的25mmol/L柠檬酸钠溶液（用0．1mol/L的氢氧化钠液调pH值至11．5）作为运行缓冲液，未涂层毛细管柱为70cm*50um.i.d)，有效长度为64cm，采用压力方式由毛细管柱的阳极旱样5s，运动电压为15kV，分离温度为20度，检测波长为254nm，并将方法测得的结果与药典规定方法测得的结果进行了比较，结果：所确定的实验条件可使土霉素与数种相关物质得到令人满意的分离，其分离效率较法定方法的为高，结论：本方法可使土霉素与数种相关物质分离，分析时间较短，能有效控制我国现行工艺生产的土霉素质量以及监控储存条件对质量的影响。     

盐酸土霉素细菌内毒素检查方法的确立

目的：考察盐酸盐霉素进行细菌内毒检查的可行性,以便控制质量使其达到出口要求。方法：抑制／增强试验及细菌内毒发值检查,结果：0．156mg.ml^-1的盐酸土霉素溶液对细菌内毒素检查无干扰,其内毒素限值符合规定,结论：盐酸土霉素可采用细菌内毒素检查法来控制其质量。     

紫外分光光度法与抗生素微生物检定法测定土霉素片含量方法比较

目前土霉素片执行的质量标准为中华人民共和国卫生部药品标准抗生素药品第一册，其含量测定采用抗生素微生物检定法。笔者采用紫外分光光度法对土霉素片的含量进行测定。现将两种不同的方法测定土霉素片的含量实验进行分析。     

解决土霉素片崩解不稳定的质量问题

目的：解决国土霉素原粉内在质量影响土霉素片崩解不稳定的质量问题。方法：经多次试验，我们采用了针对土霉素作用效能更好的崩解剂——羧甲基淀粉钠、液体石蜡进行试验。结果：完全解全了因原粉质量导致的土霉素片崩解质量问题。结论：改用羧甲基淀粉纳、液体石蜡为崩解剂效果好，保证了药品质量。     

土霉素片溶出度测定方法研究

目的建立土霉素片溶出度的测定方法。方法采用溶出度测定第二法,以盐酸溶液（9→1 000）为溶出介质,转速为50 r/min,经30 min取样,用紫外分光光度法在354 nm波长处测定土霉素片的溶出量,溶出限度为标示量的75%。结果土霉素质量浓度在6.108～21.378μg/mL范围内与吸光度线性关系良好,r=0.999 8（n=6）,平均回收率为101.31%,RSD=0.34%（n=9）。结论该方法简便、准确、重现性好,可用于土霉素片的质量控制。     

复方维锌口腔贴膜的制备及质量控制

目的:制备复方维锌口腔贴膜,并建立其质量控制方法。方法:用聚乙烯醇为成膜材料,以维生素E、硫酸锌、醋酸地塞米松、盐酸土霉素等为主药制备膜剂;采用高效液相色谱法测定其中主药维生素E的含量。结果:所制制剂鉴别、检查等符合《中国药典》2005年版相关规定;维生素E检测量线性范围为1.0～16.0μg(r=0.9999),平均回收率为(99.28±1.15)%,RSD<0.52%。结论:复方维锌口腔贴膜处方及制备工艺合理可行,质量控制方法快速、简便,准确性好,灵敏度高。     

The detection and identification of synthetic steroids in horse urine

A scheme for the detection of synthetic steroids which could be used in the “doping” of race-horses is described. The method involves extraction from urine into ethyl acetate: ether (1:1) followed by initial two-dimensional thin-layer chromatography using (1) ethyl acetate (2) methylene chloride: dioxan: water (100:50:50). Elution of the ultraviolet absorbing spots for extinction measurements is followed by further one way thin-layer chromatography as free alcohols in amyl acetate: acetone (1:1). Further chromatography of the steroid alcohols in chloroform: ether: water (80:20:0·5) on formamide-impregnated plates and chromatography of the acetates in ether helps to identify the unknown steroid. Additional identification is made by colour reactions with (1) a tetrazolium reagent (2) vanillin: perchloric acid.     

Development of a liquid chromatographic method for the determination of related substances and assay of d-cycloserine

d-cycloserine or d-4-amino-3-isoxazolidinone is an antibiotic produced by Streptomyces garyphalus and Streptomyces orchidaceus. d-Cycloserine is used in the second line treatment of tuberculosis and is often used in developing countries. Therefore, expensive high-tech techniques are not recommended for analysis. Here, a liquid chromatography method with ultraviolet detection (LC-UV) is described using a base deactivated column (Hypersil BDS column; 25 cm x 4.6 mm I.D.) kept at 45 degrees C. The gradient method uses mobile phases containing acetonitrile (ACN), 20mM sodium octane sulphonate (SOS), 0.2M potassium dihydrogen phosphate buffer pH 2.8, water: A: (4:70:10:16v/v/v/v) and B: (17:70:10:3v/v/v/v). The method proved to be robust, linear, repeatable, sensitive, selective and easy to perform. For the related substances test 50 microl of a 0.5 mg/ml d-cycloserine solution is injected. For assay, a concentration of 0.1 mg/ml is proposed to avoid overloading of the detector.     

Meta-analysis: cancer risk of low-grade dysplasia in chronic ulcerative colitis

BACKGROUND: The cancer risk of low-grade dysplasia (LGD) in chronic ulcerative colitis is variable and its management remain contentious. AIM: To determine the risk of cancer or any advanced lesion once LGD is diagnosed. METHODS: A MEDLINE, EMBASE and Pub Med search was conducted using the key words 'surveillance', 'colorectal cancer', 'low-grade dysplasia' and 'ulcerative colitis'. A random effects model of meta-analysis was used. RESULTS: Twenty surveillance studies had 508 flat LGD or LGD with dysplasia-associated lesion or mass. An average of 4.3 colonoscopies was performed/patient post-LGD diagnosis (range: 3-7.6). An average of 18 biopsies taken per colonoscopy (range: 9-24) detected 73 advanced lesions (cancer or high-grade dysplasia) pre-operatively. The cancer incidence was 14 of 1000 (95% CI: 5.0-34) person years duration (pyd) and the incidence of any advanced lesion was 30 of 1000 pyd (95% CI: 12-76). When LGD is detected on surveillance there is a ninefold risk of developing cancer (OR: 9.0, 95% CI: 4.0-20.5) and 12-fold risk of developing any advanced lesion (OR: 11.9, 95% CI: 5.2-27). CONCLUSIONS: The risk of developing cancer in patients with LGD is high. These estimates are valuable for decision-making when LGD is encountered on surveillance.     

HPLC法测定银杏叶提取物中总黄酮含量

目的:建立一种测定银杏叶提取物的高效液相色谱方法。方法:样品经简单处理后,用甲醇-水-冰乙酸(40:57.5:2.5)为流动相及C_(18)色谱柱,在254nm波长处检测,以芦丁为对照计算总黄酮。结果:该方法线性关系优良,加样平均回收率为99.41％。RSD为1.32％。结论:此方法快速、准确,亦可作为提取物制品的测定方法。     

肾康宁片中黄芪甲苷的薄层扫描法测定

目的:建立肾康宁片中黄芪甲甙含量测定方法。方法:双波长薄层扫描法,经水饱和正丁醇液冷浸超声提取,再上D101大树脂纯化,以氯仿-甲醇-水(65:30:10)下层液为展开剂,检测波长为520nm,参比波长为700nm。结果:平均加样回收率为97.8％(RSD=1.4％,n=6),标准曲线r=0.9996。结论:方法结果可靠、操作简单,可作为肾康宁片的质量控制标准。     

Monitoring paracetamol metabolism after single and repeated administration in pediatric patients with neoplastic diseases

INTRODUCTION: Paracetamol (PCM) is frequently used in pediatric patients with neoplastic disease. It is metabolized mainly by conjugation, but at therapeutic concentrations, a small fraction of the drug undergoes oxidative metabolism via cytochrome P450 forming the hepatotoxic intermediate N-acetyl-p-benzo-quinone-imine (NAPQI) which is usually conjugated with glutathione and excreted as paracetamol mercapturate and paracetamol cysteine. OBJECTIVE: The aim of this monitoring study was to evaluate PCM metabolism with minimal intervention during routine treatment with single and repeated administration in patients undergoing antineoplastic therapy. METHOD: A total of 107 urine samples collected 4-12 h after PCM administration from 29 children undergoing antineoplastic treatment, and 10 children without antineoplastic treatment were analyzed for PCM, PCM glucuronide (PCM-G), PCM sulfate (PCM-S), PCM mercapturate (PCM-M) and PCM cysteine (PCM-C). RESULTS: The median (range) percentages for metabolites in urine were: a) in children with and without chemotherapy after the first administration: PCM: 0 (0-100) and 4 (0-11)%, PCM-G: 55 (0-88) and 51 (18 - 68)%, PCM-S: 30 (0-73) and 32 (22-57)%, PCM-(M+C): 13 (0-52) and 9 (0-24)%, respectively; b) after repeated administration in children with chemotherapy: PCM: 0 (0-51)%, PCM-G: 42 (7-100)%, PCM-S: 28 (0-70)%, PCM-(M+C): 24 (0-66)%. CONCLUSION: The pattern of PCM excretion in children undergoing antineoplastic treatment regimens is highly variable. Repeated administration is associated with a significant increase in the products of oxidative metabolism. This might indicate an increase in metabolism via the hepatotoxic NAPQI.     

Elimination kinetics of ethanol in pregnant women

To evaluate the pharmacokinetics of ethanol in the early second trimester of pregnancy, ethanol concentrations simultaneously measured in the maternal blood (EtOH-MB) and in the amniotic fluid (EtOH-AF) of six pregnant women were obtained from a previous study in which a single ethanol dose of 300mgkg(-1) body weight was administered orally. For maternal blood ethanol concentration, the kinetic equation was: [Formula: see text] where k(12) and k(21) are, respectively, the rate constant of ethanol transfer from either the central compartment to the peripheral compartment or vice versa; [Formula: see text] is the maximal velocity for ethanol oxidation; and [Formula: see text] is the concentration at which half of the maximal rate of ethanol elimination is reached. The maximum concentration of EtOH in AF was 60% lower than in MB ( [Formula: see text] ). However, the AUC(0-3.5h) in AF was only 16% lower than the value for MB ( [Formula: see text] ). The k(12) ( [Formula: see text] h(-1)) was almost twice faster than k(21) ( [Formula: see text] h(-1)). The [Formula: see text] was [Formula: see text] microgml(-1)h(-1) and [Formula: see text] was [Formula: see text] microgml(-1). Our results imply that in the early second trimester, ethanol metabolism is fast. However, ethanol clearance from the AF is slower than ethanol clearance in MB. This process is widely variable, and our findings may partially explain the wide variability of ethanol's toxic effects on the fetus.