Determination of remoxipride in human plasma and urine by reversed-phase ion-pair high-performance liquid chromatography.

A sensitive method is described for the measurement of remoxipride in human plasma and urine. Remoxipride and its internal standard are extracted from plasma or urine at pH 12 with a mixture of hexane and methyl tert.-butyl ether. After washing the organic phase with base, the compounds are extracted into acid and analyzed on a C18 column with ultraviolet detection at 214 nm. The mobile phase is composed of acetonitrile and aqueous buffer (sodium perchlorate and phosphoric acid, pH 1.7). The limits of reliable quantitation for remoxipride are 12.5 and 50 ng/ml for plasma and urine, respectively. The run times are 6 min for plasma and 3 min for urine. The method has been successfully used to assay remoxipride clinical study samples. This mobile phase has also been successfully applied to the analysis of other basic drugs such as cimetidine, codeine, diltiazem and quinidine with minor modifications.     

Rapid method for the measurement of methylprednisolone and its hemisuccinate in plasma and urine following "pulse therapy" by high-performance liquid chromatography

A rapid method for the measurement of methylprednisolone and its 21-hemisuccinate ester in plasma and urine following high dose pulse therapy is described. The drugs were extracted using Extrelut columns, eluted with ethyl acetate which was evaporated to dryness and the residue was reconstituted in chromatographic mobile phase. High-performance liquid chromatography was performed on a reversed-phase column using a mobile phase of acetonitrile-acetate buffer with detection at 251 nm. No interference from any drugs or endogenous compounds has been observed. The method has been used to analyse over 200 plasma and 150 urine samples from patients with rheumatoid disease or renal failure who have received high dose methylprednisolone hemisuccinate infusions.     

Ion-pair extraction and high-performance liquid chromatographic determination of tianeptine and its metabolites in human plasma, urine and tissues

An isocratic reversed-phase ion-pair liquid chromatographic method for the determination of tianeptine and its two main metabolites in plasma, urine and tissues, using an internal standard, is reported. The influence of two stationary phases on the retention of the drugs was studied. The drugs were extracted as ion pairs, using a heptane-octanol-tetraheptylammonium bromide mixture (98:2:0.5, v/v/w) as extraction solvent. This extraction procedure yielded plasma drug recoveries of greater than 60% and allowed UV detection at 220 nm without interference from endogenous components of plasma, urine or tissues. Linear standard curves up to 1.00 micrograms/ml and drug determination down to 0.01 microgram/ml were observed. This method has been successfully applied to the analysis of human plasma and urine samples and of encephales from tianeptine-dosed rats.     

High-performance liquid chromatographic determination of BRB-I-28, a novel antiarrhythmic agent, in dog plasma and urine.

A sensitive reversed-phase high-performance liquid chromatographic (HPLC) technique with ultraviolet detection has been developed to determine the concentration of BRB-I-28 (I), a novel antiarrhythmic agent, in dog plasma and urine. The mobile phase was acetonitrile-methanol-37.5 mM phosphate buffer, pH 6.8-triethylamine (50:50:75:0.1, v/v). The compound was extracted from dog plasma and urine with chloroform after alkalinization with sodium hydroxide. The extraction recovery was 83% from plasma and 84% from urine. Good linearity (r > 0.996) was observed throughout the ranges 0.1-12.0 micrograms/ml (plasma) and 0.1-8.0 micrograms/ml (urine). Intra- and inter-assay variabilities were less than 4%. The lower limit of quantitation was 0.08 microgram/ml in either plasma or urine. HPLC analysis of plasma and urine samples from a dog treated with I has demonstrated that the method was accurate and reproducible.     

超高效液相色谱-大气压化学电离-三重四极杆质谱法同时测定血浆、尿液和瓜果类蔬菜中葫芦素B、E和I

建立了超高效液相色谱-三重四极杆质谱测定血浆、尿液和瓜果类蔬菜中葫芦素B、E和I的检测方法。血浆和尿液样品经固相支持液液萃取法（SLE）提取净化,瓜果类蔬菜样品经乙腈提取后用水稀释。以XBridge BEH C₁₈色谱柱（100 mm×3.0 mm,2.5 μm）为分析柱进行分离,以甲醇-0.025%（v/v）氨水溶液为流动相进行梯度洗脱。采用大气压化学电离源,在负离子、多反应监测（MRM）模式下检测,以夹竹桃甙作为内标物,基质工作曲线内标法定量血浆和尿液中3种葫芦素;以溶剂标准曲线外标法定量瓜果类蔬菜中的待测物。血浆和尿液中3种葫芦素的检出限均为0.03 μg/L,平均加标回收率为89.0%~113%,相对标准偏差为1.7%~12.2%（n=6）;瓜果类蔬菜中3种葫芦素的检出限为5~10 μg/kg,平均加标回收率为87.6%~114%,相对标准偏差为4.1%~11.1%（n=6）。该法简单、灵敏、准确,已应用于食用苦葫芦瓜引起中毒的病人血浆和尿液,以及葫芦瓜的检测,并检出了葫芦素B。     

Determination of exifone in human plasma and urine by high-performance liquid chromatography with electrochemical detection

A high-performance liquid chromatographic method with electrochemical detection was developed for the determination of exifone in human plasma and urine. Exifone was extracted from acidified plasma or neutralized urine with diethyl ether and the evaporated extracts were analysed on a C18 reversed-phase column. The compound was eluted in about 8 min with acetonitrile-0.3 M orthophosphoric acid (15:85, v/v) at a flow-rate of 0.9 ml/min. This method gave accurate and reproducible results; the calibration graphs were linear (r greater than 0.99) over the range of 2.8-360 nmol/l for plasma and 0.18-36 mumol/l for urine, and concentrations as low as 1 nmol/l in plasma could be quantified. These results allowed this assay to be used for determinations in single-dose pharmacokinetic studies.     

Quantitation of pancuronium, 3-desacetylpancuronium, vecuronium, 3-desacetylvecuronium, pipecuronium and 3-desacetylpipecuronium in biological fluids by capillary gas chromatography using nitrogen-sensitive detection

A sensitive and specific capillary gas chromatographic (GC) assay was developed for the quantitation of the quaternary ammonium steroidal neuromuscular blocking drugs pancuronium (PANC), vecuronium (VEC) and pipecuronium (PIP), as well as the metabolites 3-desacetylpancuronium (3-desPANC) and 3-desacetylvecuronium (3-des VEC) in plasma, bile and urine; the putative metabolite 3-desacetylpipecuronium (3-des PIP) was extracted and quantitated only in urine. The procedure employed a single dichloromethane extraction of the iodide ion-pairs of the monoquaternary or bisquaternary ammonium compounds (including internal and external standards) from acidified, ether-washed biological fluid followed by the formation of stable O-tert.-butyldimethylsilyl derivatives at the 3-hydroxy steroidal position of the metabolites. An automated capillary GC system fitted with a nitrogen-sensitive detector and an integrator was then used to analyze and quantitate both parent compounds and their derivatized metabolites. Optimal extraction, derivatization and GC conditions, as well as short-term stability and recoveries of these drugs and metabolites in plasma, are reported. Electron ionization mass spectrometry combined with GC was used to confirm the identities of compounds eluted from the column. The assay demonstrated a 10(3)-fold linear range up to 5000 ng/ml for PANC, VEC, 3-des VEC and PIP, and lower limits of detection with adequate precision of 2 ng/ml for PANC, VEC and PIP, and 4 ng/ml for 3-des VEC; 3-des PANC was linear from 8 to 500 ng/ml while 3-des PIP was linear from 25 to 1000 ng/ml. The precision (coefficient of variation) of the calibration curves for underivatized drugs and their derivatized metabolites over the linear ranges was 2-20% and the reproducibility of the assay over a range of clinical concentrations of these drugs found in human plasma was 5-16% for PANC, 2-4% for VEC and 6-11% for PIP. No interferences were detected in the assay of plasma samples from 106 surgical patients.     

Determination of cabergoline in plasma and urine by high-performance liquid chromatography with electrochemical detection.

A sensitive and selective high-performance liquid chromatographic method for the determination of cabergoline in plasma and urine has been developed. After buffering plasma and urine samples, cabergoline was extracted with a methylene chloride-isooctane mixture, back-extracted into 0.1 M phosphoric acid, then analysed by reversed-phase high-performance liquid chromatography. Quantitation was achieved by electrochemical detection of the eluate. The linearity, precision and accuracy of the method were evaluated. No interference from the biological matrices (human plasma and urine) was observed. The assay was still inadequate in terms of sensitivity for the quantitation of cabergoline plasma concentrations after a single oral dose of 1 mg of the drug to humans, but was successfully used in the determination of the urinary excretion of the drug.     

Electroanalytical determination of vinca alkaloids used in cancer chemotherapy

A differential pulse polarographic method has been developed for determination of the antineoplastic agents vincristine and vinblastine at ng ml level, in biological fluids such as plasma and urine. The vincristine and vinblastine are extracted from urine with Amberlite XAD-2. Linear calibration plots are obtained for both over the concentration range 0.005-5 mug ml . The relative standard deviations found were 1.7% for analysis of the pure drugs, 7.3% for urine and 8.6% for plasma.     

A Simple Isocratic HPLC Method for the Determination of Metoclopramide in Plasma and Urine

Abstract

Metoclopramide concentrations in plasma and urine were determined by high performance liquid chromatography using a cyanopropylsilane column and UV detection. The mobile phase consisted of 0.03M sodium acetate (pH 7.4) and acetonitrile. The plasma samples were extracted with dichloromethane after pH adjustment. Urine proteins were precipitated with acetonitrile. The reproducibility and precision of the methods were demonstrated by the analysis of samples containing 5 – 200 ng/ml plasma and 0.25 – 200 ug/ml urine.

The glucuronide and sulfate conjugates of metoclopramide were also quantitated after differential acid hydrolysis of urine samples. The conditions for acid hydrolysis were studied. The methods have been applied to the analysis of plasma and urine samples obtained from human volunteers.     

Quantitative analysis of veralipride in plasma and urine by gas chromatography-mass spectrometry and gas chromatography with flame-ionization detection

A highly sensitive and selective quantitative assay for unchanged veralipride has been developed. The compound is extracted from alkalized samples (plasma or urine) with dichloromethane and converted to its trimethylated derivative by reaction with trimethylanilinium hydroxide. The reaction mixture is then chromatographed on a 3% OV-1 column. Trimethylated derivatives of plasma samples were assayed by selected-ion monitoring in the chemical-ionization mode and quantified by comparing the intensity of the quasi-molecular ion m/z 426 (M + H) with the intensity of the corresponding ion from trideuterated internal standard, m/z 429 (M + H). Flame-ionization detection was used for the assay of urine samples. The peak height ratio of trimethylated veralipride over trimethylated sulpiride, the internal standard, was used for quantitation of urine samples. A relative standard deviation of less than 10% was found when quantifying 10 ng/ml veralipride in plasma or 1 microgram/ml in urine.     

Measurement of bumetanide in plasma and urine by high-performance liquid chromatography and application to bumetanide disposition.

A high-performance liquid chromatographic method for the measurement of bumetanide in plasma and urine is described. Following precipitation of proteins with acetonitrile, bumetanide was extracted from plasma or urine on a 1-ml bonded-phase C18 column and eluted with acetonitrile. Piretanide dissolved in methanol was used as the internal standard. A C18 Radial Pak column and fluorescence detection (excitation wavelength 228 nm; emission wavelength 418 nm) were used. The mobile phase consisted of methanol-water-glacial acetic acid (66:34:1, v/v) delivered isocratically at a flow-rate of 1.2 ml/min. The lower limit of detection for this method was 5 ng/ml using 0.2 ml of plasma or urine. Nafcillin, but not other semi-synthetic penicillins, was the only commonly used drug that interfered with this assay. No interference from endogenous compounds was detected. For plasma, the inter-assay coefficients of variation of the method were 7.6 and 4.4% for samples containing 10 and 250 ng/ml bumetanide, respectively. The inter-assay coefficients of variation for urine samples containing 10 and 2000 ng/ml were 8.1 and 5.7%, respectively. The calibration curve was linear over the range 5-2000 ng/ml.     

Simultaneous determination of cefamandole and cefamandole nafate in human plasma and urine by high-performance liquid chromatography with column switching

A high-performance liquid chromatographic method with column switching has been developed for the simultaneous determination of cefamandole and cefamandole nafate in plasma and urine. The plasma and urine samples were injected onto a precolumn packed with Corasil RP C18 (37-50 microns) after simple dilution with an internal standard solution in 0.05 M phosphoric acid. Polar plasma and urine components were washed out using 0.05 M phosphoric acid. After valve switching, the concentrated drugs were desorbed in back-flush mode and separated by a reversed-phase C8 column with methanol-5 mM tetrabutylammonium bromide (45:55, v/v) as the mobile phase. The method showed excellent precision with good sensitivity and speed, and a detection limit of 0.5 microgram/ml. The total analysis time per sample was less than 30 min, and the mean coefficients of variation for intra- and inter-assay were both less than 4.9%. The method has been successfully applied to plasma and urine samples for human volunteers after intravenous injection of cefamandole nafate.     

HPLC Assay for Trimethoprim in Plasma and Urine

Abstract

A sensitive HPLC method for the quantitation of trimethoprim in plasma and urine was developed using fluorescence detection. Plasma (or urine) samples were made basic by the addition of 3.8N sodium hydroxide and extracted with chloroform:2-propanol (95:5). After evaporation of the organic layer, a portion of the residue was analyzed by HPLC with fluorescence detection. The minimum detectable quantity is 0.1 μg/ml for this method. This method has been applied to the analysis of plasma and urine obtained from subjects after a single 160 mg dose of trimethoprim.     

稳定同位素稀释离子色谱-三重四极杆质谱法测定血浆和尿液中的氟乙酸

建立了离子色谱-三重四极杆质谱测定血浆和尿液样品中氟乙酸（MFA）的方法。血浆样品经高氯酸超声提取,尿液样品经高氯酸酸化,血浆和尿液提取液在pH 0.5~1.0条件下用叔丁基甲醚（MTBE）萃取,萃取液经氮吹浓缩后溶于0.1%（v/v）氨水溶液。以Ionpac AS 19型阴离子色谱柱为分析柱,在线自动产生的氢氧化钾作为淋洗液进行梯度分离,柱流出液经阴离子抑制器抑制后进入质谱系统。采用电喷雾电离源,在负离子、多离子监测（MRM）模式下检测,¹³C₂-氟乙酸稳定同位素内标法定量。血浆和尿液样品中氟乙酸的平均加标回收率为96.2%~120%,相对标准偏差为1.1%~13.1%（n=6）,方法的检出限（S/N=3）分别为0.03 μg/L和0.1 μg/L。该法简单、灵敏、准确,可用于生物样品中氟乙酸的检测。     

High-performance liquid chromatographic analysis of tiaprofenic acid and its metabolites in plasma and urine by direct injection

A rapid, convenient, sensitive and selective reversed-phase high-performance liquid chromatographic method was developed to measure tiaprofenic acid, its reduced and oxidized metabolites and their conjugates in biological fluids. The method involved direct injections of plasma and urine samples into the chromatograph before and after alkaline hydrolysis of the conjugates. Concentrations as low as 0.5 micrograms/ml of the drug in plasma and urine were quantifiable. The method was suitable for analysis of tiaprofenic acid and its metabolites in biological fluids after administration of therapeutic doses. Several other non-steroidal anti-inflammatory drugs which were applied to the system did not interfere with the assay.     

Determination of the antiplatelet agent. KB-3022, and its metabolite by high-performance liquid chromatography

A rapid, accurate and reproducible high-performance liquid chromatographic method for the simultaneous determination of a new antiplatelet agent, ethyl 2-[4,5-bis(4-methoxyphenyl)thiazol-2-yl]pyrrol-1-ylacetate (KB-3022), and its main metabolite, 2-[4,5-bis(4-methoxyphenyl)thiazol-2-yl]pyrrol-1-ylacetic acid (desethyl KB-3022), in biological fluids has been developed. KB-3022 and desethyl KB-3022 in plasma or urine were extracted with a mixture of n-hexane and dichloromethane (1:1), separated on a reversed-phase C18 column with a mixture of 0.01 M (NH4)2HPO4 (pH 3.0), acetonitrile and isopropyl alcohol as a mobile phase, and quantitated by ultraviolet absorbance measurement at 340 nm. 4-[2-(4,5-bis(4-methoxyphenyl)thiazol-2-yl)pyrrol-1-yl]butyric acid was used as an internal standard. The detection limit of KB-3022 in plasma was 3 ng/ml, and that of KB-3022 in urine and desethyl KB-3022 in plasma or urine was 1 ng/ml. The coefficients of variation for the determination of KB-3022 or desethyl KB-3022 in plasma or urine were below 5.6%. This method was applied to the determination of the plasma concentration of KB-3022 and desethyl KB-3022 after intravenous administration to rats.     

Analysis of buprenorphine and its N-dealkylated metabolite in plasma and urine by selected-ion monitoring

A selected-ion monitoring method was developed for determination of buprenorphine and its N-dealkylated metabolite (norbuprenorphine) in human plasma and urine. N-Propylnorbuprenorphine was added as internal standard to 2-3 ml of sample and the alkaloids were extracted with toluene-2 butanol at pH 9.4. After back-extraction in dilute sulphuric acid, the compounds were heated at 110 degrees C. This procedure led to quantitative loss of methanol followed by ring formation between the 6-methoxy group and the branched side-chain of all compounds. The derivatives were extracted into dichloromethane-2-butanol and treated with pentafluoropropionic anhydride. The resulting derivatives were suitable for selected-ion monitoring analysis. The coefficient of variation was found to be 4.5% at 5 ng/ml and 8.9% at 50 ng/ml in urine. The corresponding values for plasma were 6.2% and 5.3%, respectively. The lower limit of detection in plasma was 150 pg/ml, permitting analysis of plasma levels of buprenorphine for 24 h and urine levels of buprenorphine and norbuprenorphine for more than seven days after a therapeutic dose of buprenorphine. This method is the first with sufficient specificity and sensitivity for characterization of the clinical pharmacokinetics of buprenorphine.     

Simultaneous determination of gemfibrozil and its metabolites in plasma and urine by a fully automated high performance liquid chromatographic system

Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid), a lipid-lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.     

体液中-叶萩碱检测方法的研究

本文报道了用气相色谱(GC)及气相色谱-质谱联用(GC/MS)检出人体液中一叶萩碱的方法.尿样经碱化后用乙醚直接萃取,回收率为72.1％;血浆样品用Sep-pak小柱提取,回收率为 43.9％,GC/MS的检测限为 20ng.方法快速、简便、准确.