荷移反应测定克拉霉素片的含量

目的 采用荷移反应法快速测定克拉霉素胶囊中的有效含量.方法 通过克拉霉素与2,4-二硝基苯酚的荷移反应,采用分光光度法测定克拉霉素片的含量.结果 克拉霉素与2,4-二硝基苯酚在乙醇-丙酮介质中发生电荷转移反应,产物的最大吸收波长为364 nm,表观摩尔吸光系数为1.55×10~4 L·mol~(-1)·cm~(-1),荷移络合物的组成比为1:1,相对标准偏差为0.98%(n=8),药物5～45 mg·L~(-1)与吸光度呈线性关系,回收率符合要求.结论 所用方法简便易行,条件易控,灵敏度高.     

头孢米诺钠与2,4-二硝基苯酚的荷移反应及其测定

目的建立用荷移分光光度法测定头孢米诺钠含量的方法。方法利用头孢米诺钠与2,4-二硝基苯酚在甲醇-丙酮介质中反应,形成电荷转移络合物,采用分光光度法测定。结果荷移络合物在403nm处有最大吸收,表观摩尔吸光系数为=ε1.47×104L/(m o l.cm),药物浓度在4~40μg/m l范围内符合比耳定律线性关系,方法平均回收率大于97.0%。结论荷移分光光度法简便、准确、灵敏,可作为头孢米诺钠制剂的含量测定方法。     

阿奇霉素片的茜素红荷移分光光度法测定

阿奇霉素与茜素红在乙醇-水溶液中发生荷移反应,由此建立了荷移分光光度法测定阿奇霉素片的含量.荷移反应生成1:2型络合物,最大吸收波长为538 nm,摩尔吸收系数为1.23×10 4L·mol-1·cm-1.阿奇霉素在10～60μg/ml浓度范围内线性关系良好.含量测定结果与HPLC法结果基本相符.     

荷移分光光度法测定尼可占替诺

目的:通过尼可占替诺与氯冉酸的荷移反应来测定脑脉康制剂中尼可占替诺的含量。方法:用721型分光光度计,利用分光光度法进行测定。结果:反应在乙醇-丙酮(1:1)介质中进行,反应产物(荷移络合物)的最大吸收波长为530nm,表观摩尔吸收系数为1.18×10~3L·moL~(-1)·cm~(-1),RSD为0.9％(n=6),药物浓度在20～320mg·L~(-1)范围内呈线性关系。结论:此方法简便易行,条件易于控制,对实际样品的测定结果令人满意。     

四苯硼钠法测定氯氮(艹卓)的含量

本文介绍一种可有效地测定氯氮艹卓 含量的方法。在pH =4 .0的HAc NaAc缓冲溶液中 ,加入过量的四苯硼钠与氯氮艹卓反应可形成分子比为 1∶1的定量沉淀 ,过滤 ,弃去初滤液。以溴酚蓝为指示剂 ,用十六烷基三甲基溴化铵标准溶液滴定续滤液中过量的四苯硼钠 ,方法简便 快速 ,应用于多批氯氮艹卓 原料药样品的测定 ,其回收率为 99.5 8%～ 10 0 .4 % ,相对误差<± 0 .5 0 % ,与中国药典法测得的结果基本一致     

分光光度法测定药物制剂中维生素C的含量

用1-氯-2,4-二硝基苯(CDB)作为显色剂,在碱性介质中与VC反应形成黄红色产物,在380 nm处有最大吸收。摩尔吸收系数为0.14×10~4Lmol~(-1)cm~(-1),VC在0.12～0.6mg/10 ml范围内符合比尔定律。试剂所有试剂均为分析纯。 0.1 M碳酸钠:用水配制; 0.001M CDB:用二甲基亚砜(DMSO)和水(80∶20)混合液配制。供试品溶液 0.3%(W/V)VC水溶液:当天配制; 片剂和胶囊水溶液:临用前配制。测定步骤准确吸取0.04～0.2 ml的VC,加1.5 mlCDB和1.5 ml碳酸钠溶液置10 ml容量瓶中,反应20分钟,加H_2O-DMSO(80∶20)混合液至刻度,同时以试剂为     

琥乙红霉素与氯冉酸的荷移反应及其测定

利用琥乙红霉素与氯冉酸在丙酮 -乙醇介质中发生电荷转移反应 ,形成电荷转移络合物 ,采用可见光光度法测定了琥乙红霉制剂的含量。结果显示 ,荷移反应生成的荷移络合物在 5 2 6nm处有最大吸收 ,表观摩尔吸光系数是 1.62× 10 3L· mol- 1·cm- 1 ,应用等摩尔连续变换法和斜率比法测得荷移络合物的组成比为 1∶ 1,稳定常数是 6.6× 10 4。药物浓度在 0～ 5 0 0 mg/ L范围内服从比耳定律 ,方法平均回收率在 98.0 %以上 ,RSD为 1.71% (n=6)。     

四氯苯醌荷移反应在喹诺酮抗生素含量测定中的特异性

目的：对荷移反应在喹诺酮抗生素含量测定中的特异性进行系统的评价。方法：通过对不同结构的喹诺酮抗生素瓜的测定，分析喹诺酮类抗生素结构对荷移反应的；通过对环丙沙星在其光降解产物中的荷移反应的测定，评价荷移反应的特异性。结果：荷移反应受喹诺酮类抗素哌嗪基４－位氮原子（电子给予体）及其相邻３位、５位上取代基的干扰，４－位氮原子上具有取代基的药物不能形成稳定的荷移反应络合物，３位、５位上的取代基可导致荷移反     

氯冉酸荷移分光光度法测定注射用头孢硫脒

目的:建立测定注射用头孢硫脒含量的方法。方法:利用氯冉酸与头孢硫脒在无水乙醇溶液中发生荷移反应,形成荷移络合物,采用分光光度法测定。结果:荷移络合物在530nm处有最大吸收,表观摩尔吸收系数为1.164×103L/(mol·cm),药物浓度在0.007840～0.1702mg/mL内符合朗伯比尔定律。方法的平均回收率在98.0%以上。结论:该方法快速、准确,可用于测定药物制剂中头孢硫脒的含量。     

法莫替丁与氯醌酸电荷转移反应中超分子作用及其应用

目的：建立电荷转移分光光度法测定片剂中法莫替丁的含量。方法：法莫替丁作为电子给体，氯醌酸作为电子受体，两者反应生成荷移化合物，在517nm处有最大吸收，对片剂中法莫替丁的含量进行了测定。同时对非水体系中超分子作用机制进行研究。结果：法莫替丁与氯醌酸形成荷移化舍物的表观百分吸收系数为25．4±2．5，稳定常数K为（3．1±0．9）×10^6，测定法莫替丁的线性范围为16．8～285．6mg·L^-1，精密度RSD不大于3．0％，检测限2mg·L^-1，方法回收率为（100．3±2．1）％。在丙酮溶剂中，微量醇对荷移化合物有超分子作用。结论：电荷转移分光光度法测定片剂中法莫替丁的含量快速、准确。     

原儿茶醛分析方法的研究——Ⅰ.原儿茶酸存在下测定原儿茶醛的比色方法

基于间苯三酚和原儿茶醛在硫酸存在下缩合生成有色化合物的反应而建立了原几茶醛的比色方法。本法灵敏、操作简单、结果稳定。大量存在的原儿茶酸不干扰测定。     

A simple photokinetic method for the determination of nitroprusside in biological and pharmaceutical samples

A simple method has been developed for the determination of nitroprusside in human serum and pharmaceutical preparations. The new method is based on the strong inhibitory effect of nitroprusside on the photochemical reduction of phloxin by ethylenediaminetetra-acetic acid. The rate measurements are accomplished very simply by measuring the time needed for the absorbance to be reduced to 1/10th of its initial value. Optimal conditions for the determination of nitroprusside at concentrations of 15-200 ng ml-1 are described.     

Determination of sulphated glycosaminoglycans by automated potentiometric titration with simple coated-wire electrodes

A method for the determination of sulphated glycosaminoglycans is based on their precipitation with (1-ethoxycarbonyl)pentadecyltrimethylammonium bromide (Septonex), the excess of which is back-titrated with sodium tetraphenylborate. The titration is monitored by a simple coated-wire ion-selective electrode with a plasticized poly(vinyl chloride) membrane on aluminium wire. Under certain conditions the results are almost independent of the relative molecular mass of glycosaminoglycans. The method has been applied to the determination of the active ingredient in the pharmaceutical preparation, heparon injection.     

Conductometric and indirect AAS determination of antimalarials

Two methods are described for the determination of amodiaquine hydrochloride, chloroquine phosphate and primaquine phosphate, based on the formation of their ion-associates with [Cd(2+), Co(2+), Mn(2+) and Zn(2+)] thiocyanate, ammonium reineckate and/or sodium cobaltinitrite. The molar combining ratio reveal that (1:1) (drug:reagent) ion associates are formed for all reagents except for ammonium reineckate which form (1:2) ion associates with all studied drugs. The optimum conditions for the ion-association have been studied. Conductometric method was applied for the direct determination of the suggested drugs in bulk powders, whereas indirect atomic absorption spectrometric method, depending on the measurement of the excess metal ion present in supernatant solutions after precipitation of the ion associates is used to calculate the drug concentration. Optimum concentration ranges for the determination of aminoquinoline antimalarial drugs under consideration were 0.46-12.90 and 0.155-3.87 mg using conductometric and indirect atomic absorption spectral methods, respectively. The proposed procedures have been applied successfully to the analysis of these drugs in certain formulations and the results are favourably comparable to the official methods.     

Study on the charge-transfer reaction between 7,7,8,8-tetracyanoquinodimethane and drugs

The charge-transfer (CT) reaction between 7,7,8,8-tetracyanoquinodimethane (TCNQ) as a pi-electron acceptor and cinnarizine, analgin, norfloxacin as electron donors have been studied by spectrophotometric method. The charge transfer complexes between TCNQ and these drugs have stable blue color, therefore a simple, rapid, accurate and sensitive method for determination of these drugs has been developed. The optimization of the experimental conditions is described. Beer's law is obeyed in the ranges 2-18, 2-18 and 4-32 microg/ml for cinnarizine, analgin and norfloxacin, respectively. The apparent molar absorptivity of CT complexes at 743 nm is 1.58x10(4), 1.71x10(4) and 8.91x10(3) l/mol per cm, respectively. The composition of all these CT complexes are found to be 1:1 by different methods. The relative SDs are less than 3% (n = 10). The proposed method has been applied to the determination of these drugs in their each pharmaceutical dosage forms with satisfactory results.     

Quantitative determination of some pharmaceutical piperazine derivatives through complexation with iron(III) chloride

A simple, accurate and sensitive spectrophotometric method has been developed for the determination of three pharmaceutical piperazine derivatives, namely ketoconazole (KC), trimetazidine hydrochloride (TMH) and piribedil (PD). This method is based on the formation of yellow orange complexes between iron(III) chloride and the investigated drugs. The optimum reaction conditions, spectral characteristics, conditional stability constants and composition of the water soluble complexes have been established. The method permits the determination of KC, TMH and PD over a concentration range 1-15, 1-12 and 1-12 microg ml(-1), respectively. Sandell sensitivity is found to be 0.016, 0.013 and 0.013 microg cm(-2) for KC, TMH and PD, respectively. The method was sensitive, simple, reproducible and accurate within +/-1.5%. The method is applicable to the assay of the three drugs under investigation in different dosage forms and the results are in good agreement with those obtained by the official methods (USP and JP).     

Determination of acetoacetate in urine by solid-phase spectrophotometry

A method for the determination of acetoacetate has been developed based on solid-phase spectrophotometry (SPS). The acetoacetate reacts with nitroprusside and glycine and the reaction product is sorbed on Dowex 1-X8 resin. The absorbance of the resin phase at 590 and 720 nm is measured directly. The calibration graph is linear up to 3.3 mg l-1 and the RSD is 1.9%. The detection limit is 7.6 micrograms l-1. The method has been applied to the determination of acetoacetate in normal and diabetic subjects' urine without pretreatment of the samples, and the results compared with those of 1H-NMR and homogeneous nitroprusside methods.     

Determination of dopamine by flow-injection analysis coupled with luminol-hexacyanoferrate(III) chemiluminescence detection

A novel flow-injection method (FIA) for the determination of dopamine based on the inhibition of the intensity of chemiluminescence (CL) from luminol-hexacyanoferrate(III) system in basic medium is described. The present method allows the determination of dopamine over the range 30-100 microg l(-1) and 400-3000 microg l(-1). The relative standard deviation is 2.32% for 70 microg l(-1) dopamine and 1.22% for 1500 microg l(-1) dopamine (n = 20). The detection limit is 5 microg l(-1) with the sampling rate of 135 samples h(-1). This method has been applied for the determination of dopamine in commercial pharmaceutical injection samples. The results obtained by this method agreed with those by the official method.     

喹诺酮药物荷移反应的研究

目的：研究分光光度法测定吡哌酸、氟哌酸和乳酸环丙氟哌酸的含量,方法：基于在水溶液中药物与２,４二硝基酚生成荷移络合物。结果：表现摩尔吸光系数ε＝１３４×１０４～４２０×１０４Ｌ·ｍｏｌ－１·ｃｍ－１,络合物组成均为１∶１,络合物的最大吸收波长λｍａｘ＝３９７４～４０４０ｎｍ,相对标准偏差为１４３％～３６５％。结论：应用本方法测定吡哌酸、氟哌酸和乳酸环丙氟哌酸药物制剂含量可得到满意的结果。     

Determination of 2,6-dimethylaniline and o-toluidine impurities in preparations for local anaesthesia by the HPLC method with amperometric detection

2,6-Dimethylaniline (2,6-DMA) and o-toluidine (o-TLD) together with their decomposition products are potential technological impurities of Pharmaceuticals used for local anaesthesia, in which lidocaine and prilocaine appear as active substances. Pharmacopoeial analytical methods for the determination of these impurities are little sensitive (from about 1 microg ml(-1)) and accurate and provide results which are difficult to interpret. Taking the above into account, a sensitive and specific amperometric method has been developed, which enables, after separation with the use of HPLC, an accurate determination of the content of 2,6-DMA and o-TLD in various pharmaceutical preparations. The determinations were performed at a glassy carbon electrode at a potential of +0.85 V. The limit of detection for both 2,6-DMA and o-TLD was 0.8 ng ml(-1). On the other hand, the limit of quantitation, considering a signal to noise ratio, was 1.5 ng ml(-1). The developed method allows to determine low concentrations of the impurities in question, which are hardly 1/120000 of the main substance. Preparation and determination of samples is carried out in a relatively short time, thus the method can be applied to routine investigations. Statistical evaluation of the obtained results shows that the accuracy and precision of the elaborated HPLC-ED method is good.