High-performance liquid chromatographic determination of glipizide in human plasma and urine

A sensitive and selective high-performance liquid chromatographic method for determination of intact glipizide in human plasma or urine has been developed. The plasma and urine samples were acid-buffered, before tolbutamide was added as internal standard. The samples were extracted with benzene, and the organic layer was evaporated to dryness. The residue was dissolved in equilibrated mobile phase (acetonitrile-0.01 M phosphate buffer pH 3.5, 35:65), and an aliquot of 20 microliters was chromatographed on a Spherisorb ODS reversed-phase column. Quantitation was achieved by monitoring the ultraviolet absorbance at 275 nm. The response was linear (0-1000 ng/ml) and the detection limit was 5-10 ng/ml in plasma or urine. The within-assay variation was less than or equal to 10%. No interferences from metabolites or endogenous constituents were observed. The utility of the assay was demonstrated by determining glipizide in samples from a diabetic subject receiving a therapeutic dose of 5 mg of the drug.     

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.     

Rapid assays of clozapine and its metabolites in dried blood spots by liquid chromatography and microextraction by packed sorbent procedure

A novel analytical approach has been developed for the determination of clozapine and its metabolites in dried blood spots on filter paper, using a chromatographic method coupled with a microextraction by packed sorbent procedure. The analytes were separated on a RP-C18 column using a mobile phase composed of 20% methanol, 16% acetonitrile and 64% aqueous phosphate buffer. Coulometric detection was used, setting the guard cell at +0.050 V, the first analytical cell at -0.200 V and the second analytical cell at +0.500 V. Clozapine and its metabolites were extracted from dried blood spots with phosphate buffer and, then, a microextraction by packed sorbent procedure for the sample clean-up was implemented obtaining good extraction yields. The calibration curve was linear over the 2.5-1000 ng mL(-1) blood concentration ranges for all the analytes. The method validation gave satisfactory results in terms of sensitivity, precision, selectivity and accuracy. The analytical method was successfully applied to dried blood spots from several psychiatric patients for therapeutic drug monitoring purpose.     

HPLC method for determination of diclofenac in human plasma and its application to a pharmacokinetic study in Turkey

A simple high-performance liquid chromatography (HPLC) method has been developed for determination of diclofenac in human plasma. The method was validated on Ace C(18) column using UV detection. The mobile phase consisted of 20 mM phosphate buffer (pH 7) containing 0.1% trifluoroacetic acid-acetonitrile (65:35, v/v). Calibration curve was linear between the concentration range of 75-4000 ng/mL. Intra- and inter-day precision values for diclofenac in plasma were less than 3.6, and accuracy (relative error) was better than 5.3%. The limits of detection and quantification of diclofenac were 25 and 75 ng/mL, respectively. Also, this assay was applied to determine the pharmacokinetic parameters of diclofenac in healthy Turkish volunteers who had been given 50 mg diclofenac.     

有机酸类化合物的反相高效液相色谱法的分离条件研究

 研究了在用RP HPLC法测定有机酸时如何对流动相的酸度进行控制 ,给出了流动相最佳pH的选择通式 :色谱柱允许的最低 pH值≤pH≤pKa- 2 ;研究了流动相中甲醇、乙腈存在时对此通式的影响。用研究得出的结论选择了测定甲酸、乙酸、丙酸、丁酸和丙二酸、丁二酸、戊二酸、己二酸时的色谱条件 ,并且研究了每种酸在各自浓度范围内测定的线性关系、回归方程、相关系数以及相对标准偏差。实验显示 ,在选定的色谱条件下进行分析测试时 ,各种酸的线性相关系数r >0 9995 ,相对标准偏差RSD <0 90 %。     

High-performance capillary zone electrophoretic assay for markers of diabetic nephropathy in plasma and urine

A new high-performance capillary zone electrophoretic assay for creatine (Cr), creatinine (Cn), urea (U) and uric acid (Ua), markers of human diabetic nephropathy, both in plasma and urine has been developed with UV detection at 200 nm. The plasma sample was deproteinized with trichloroacetic acid and centrifuged at 10 000 rpm for 10 min. The urine sample was diluted 20-fold with buffer before analysis. The optimum separation conditions for the markers was investigated with respect to the concentration of the buffer, the pH, the voltage and the capillary temperature. Baseline separation was achieved in 25 mmol/L phosphate buffer (pH 3.45) using a 21 cm x 75 microm I.D. fused-silica capillary at 40 degrees C with an electric field of 1190 V/cm. The calibration curves showed good linearity in the range 3.5-1000, 0.18-700, 500-5000 and 2-800 microM (r2 min > 0.998) for Cr, Cn, U and Ua, respectively. The proposed method also has a high reproducibility (peak area RSD max < 3%) and has been successfully applied to the determination of clinical samples.     

Micro-method for the determination of roxithromycin in human plasma and urine by high-performance liquid chromatography using electrochemical detection

A simple and sensitive high-performance liquid chromatographic micro-method for the determination of roxithromycin in human plasma and urine is described. A dichloromethane extract of the sample was chromatographed on a C18 reversed-phase column with acetonitrile-83 mM ammonium acetate-methanol (55:23:22, v/v) adjusted to pH 7.5 with acetic acid as the mobile phase. Roxithromycin and the internal standard, erythromycin, were detected by dual coulometric electrodes operated in the oxidative screen mode. The applied cell potential of the screen electrode was set at +0.7 V and the sample electrode at +0.9 V. The intra- and inter-assay coefficients of variation were less than or equal to 7.0%. The detection limit (signal-to-noise ratio = 3) was 0.1 microgram/ml for both plasma and urine. A study of drug stability during sample storage at 4, 20 and 37 degrees C showed no degradation of roxithromycin. The method is convenient for clinical monitoring and pharmacokinetic studies.     

Determination of human plasma protein binding of baicalin by ultrafiltration and high-performance liquid chromatography

A simple and selective HPLC assay was developed and utilized for determination of human plasma protein binding of baicalin. The method involved solid-phase extraction and reversed-phase chromatographic separation with a mobile phase of acetonitrile-0.02 mol/L phosphate buffer (pH 2.5; 25:75, v/v) and UV detection at 276 nm. The standard curve for baicalin was linear over the concentration range 0.1-20 microg/mL and the limit of detection was 0.02 microg/mL. The absolute recovery was greater than 76%. The intra-day and inter-day variations were less than 10%. Ultrafiltration technique was applied to determining the plasma protein binding of baicalin in human plasma. Results show the plasma protein binding of baicalin was in the range 86-92% over all the concentrations studied and the protein binding association constant was determined to be 1.21 x 10(5) L/mol at 4 degrees C.     

Enantiospecific high-performance liquid chromatographic assay with fluorescence detection for the monoamine oxidase inhibitor tranylcypromine and its applicability in pharmacokinetic studies.

In order to be able to measure low concentrations of tranylcypromine enantiomers in biological material, chiral fluorescent derivatization and high-performance liquid chromatography (HPLC) were employed. The internal standard S-(+)-amphetamine and borate-sodium hydroxide buffer pH 11 were added to plasma or urine sample aliquots. o-Phthaldialdehyde was used for precolumn derivatization in combination with the chiral mercaptan N-acetylcysteine. HPLC resolution of the diastereoisomeric derivatives was possible on an octadecylsilane column. The mobile phase consisted of sodium phosphate buffer solution pH 6.5, methanol and tetrahydrofuran. The fluorescence of the eluate was monitored at 344/442 nm. The intra-day coefficients of variation were below 10%, the limit of determination was 0.5 ng/ml. The assay was found to be applicable for routine analyses in a preliminary pharmacokinetic study, in which an oral dose of 20 mg racemic tranylcypromine sulfate was administered to three healthy volunteers. The plasma concentrations were generally low, and those of S-(-)-tranylcypromine significantly exceeded those of the R-(+)-enantiomer. Average maximum concentrations were 57.5 and 6.3 ng/ml for S- and R-tranylcypromine, respectively. While S-tranylcypromine was well detectable within the whole study period (8 h), R-tranylcypromine concentrations fell below the detection limit after 4 h in two out of the three studied volunteers.     

Determination of cibenzoline in plasma and urine by high-performance liquid chromatography

A rapid, sensitive and selective high-performance liquid chromatographic (HPLC) assay was developed for the determination of cibenzoline (CipralanTM) in human plasma and urine. The assay involves the extraction of the compound into benzene from plasma or urine buffered to pH 11 and HPLC analysis of the residue dissolved in acetonitrile-phosphate buffer (0.015 mol/l, pH 6.0) (80:20). A 10-microns ion-exchange (sulfonate) column was used with acetonitrile-phosphate buffer (0.015 mol/l, pH 6.0) (80:20) as the mobile phase. UV detection at 214 nm was used for quantitation with the di-p-methyl analogue of cibenzoline as the internal standard. The recovery of cibenzoline in the assay ranged from 60 to 70% and was validated in human plasma and urine in the concentration range of 10-1000 ng/ml and 50-5000 ng/ml, respectively. A normal-phase HPLC assay was developed for the determination of the imidazole metabolite of cibenzoline. The assays were applied to the determination of plasma and urine concentrations of cibenzoline and trace amounts of its imidazole metabolite following oral administration of cibenzoline succinate to two human subjects.     

反相高效液相色谱法测定化妆品中L-抗坏血酸磷酸镁含量

L-抗坏血酸磷酸镁(AS-PM)用在化妆品中作增白剂和抗辐射剂。AS-PM是极性分子,通常使用一个阴离子交换柱进行色谱分离,本文用四氢呋喃。磷酸盐缓冲溶液溶解稀释化妆品样品后,在氨丙基柱上以乙腈一磷酸盐缓冲溶液为流动相测定其中的AS-PM。     

高效液相色谱法同时测定假尿核苷和肌酐的研究及应用

本文用高效液相色谱法同时测定人尿中假尿核苷和肌酐,研究了流动相的pH值变化对色谱行为的影响,方法简便、快速,已成功地用于对正常人、肺部感染及肺癌患者的尿样分析,其结果有显著性差异。     

High-performance liquid chromatographic measurement of 8-methoxypsoralen in plasma

Summary A simple high-performance liquid chromatographic method for the measurement of 8-Methoxypsoralen (8-MOP) in human plasma following a single 40mg dose has been described. After addition of phosphate-NaOH buffer, pH 12, and internal standard (trimethylpsoralen), the sample is vortex-mixed with diisopropylether. The resulting extract is analysed on a reverse phase column using phosphoric acid (0.05% v/v): acetonitrile (1:1) as mobile phase, and U.V. detection at 220nm. No interference from endogenous sources has been observed. The limit of sensitivity of the assay is 5ng/ml plasma. The measuring range is between 10–700ng 8-MOP/ml plasma, to be expected from oral doses of 0.6mg 8-MOP/kg body weight, and corresponds to the therapeutic plasma concentration. The relative standard deviation at 50ng/ml level of 8-MOP is 3.6%.     

Fast high-performance liquid chromatographic determination of R(+)[(5,6-dichloro-2,3,9,9a-tetrahydro-3-oxo-9a-propyl-1-H-fluoren-7-yl)oxy]acetic acid in human plasma and urine

A simple and rapid high-performance liquid chromatographic method for the determination of R[(5,6-Dichloro-2,3,9,9a-tetrahydro-3-oxo-9a-propyl-1-H-fluoren-7-yl)oxy]acetic acid (I) in human plasma and urine is described. The method utilizes Bond-Elut® cartridge facilitate the drug extraction. Analysis is performed on a short reversed-phase column with a mobile phase consisting of acetonitrile and phosphate buffer and quantification is carried out by ultraviolet detection with a wave-length set at 340 nm. The method is linear and reproducible for both plasma and urine analyses (0.25–50) μg/mL) with the detection limit of 125 ng/mL of plasma and urine. Plasma and urine concentrations of / at selected time intervals following I.V. administration of single rising doses are presented.     

Determination of amdinocillin in plasma and urine by high-performance liquid chromatography

A rapid, sensitive and specific high-performance liquid chromatographic (HPLC) assay was developed for the determination of amdinocillin (formerly mecillinam) in human plasma and urine. The assay is performed by direct injection of a plasma protein-free supernatant or a dilution of urine. A 10 micrometer muBondapak phenyl column with an eluting solvent of water--methanol--1 M phosphate buffer, pH 7 (70:30:0.5) was used, with UV detection of the effluent at 220 nm. Azidocillin potassium salt [potassium-6-(D-(-)-alpha-azidophenyacetamido)-penicillanate] was used as the internal standard and quantitation was based on peak height ratio of amdinocillin to that of the internal standard. The assay has a recovery of 74.4 +/- 6.3% (S.D.) in the concentration ranges of 0.1-20 microgram per 0.2 ml of plasma with a limit of detection equivalent to 0.5 microgram/ml plasma. The urine assay was validated over a concentration range of 0.025-5 mg/ml of urine, and has a limit of detection of 0.025 mg/ml (25 microgram/ml) using a 0.1-ml urine specimen per assay. The assay was applied to the determination of plasma and urine concentrations of amdinocillin following intravenous administration of a 10 mg/kg dose of amdinocillin to two human subjects. The HPLC and microbiological assays were shown to correlate well for these samples.     

Simultaneous determination of free and bound adriamycin, adriamycinol, adriamycinone and duanorubicin in plasma using column-switching technique and protein-coated pre-columns

Adriamycin, adriamycinol, adriamycinone and duanorubicin were simultaneously determined by the development of an on-line plasma clean-up system. A short protein-coated Lichrosorb, RP-8, RP-2, CN and muBondapak phenyl as well as ODS silica have been examined for their performance as pre-columns. The drugs and metabolites were separated from weakly retained plasma components through two steps; phosphate buffer saline, pH 7.4 and 15% acetonitrile in 0.1 M sodium dihydrogen phosphate, pH 3. The chromatographic conditions were: ODS/TM column, flow rate 1 ml/min, 35% acctonitrile in 0.1 M sodium dihydrogen phosphate (pH 3) containing 0.3% heptafluorobutyric acid as mobile phase. The detection was carried out using fluorescence monitor operated at an emission 555 nm and excitation 460 nm. Good resolution was obtained within 13 min. This method is reproducible for analysis of drugs and metabolites (99.3-100.1%, CV < 2%) in plasma.     

高聚物型色谱柱分离乙酰半胱氨酸及其有关物质

考察高聚物型色谱柱(聚苯乙烯-二乙烯基苯(PS-DVB)麦科菲反相高效液相色谱柱,MKF-RP-MH)分离乙酰半胱氨酸以及有关物质的适用性。采用MKF-RP-MH色谱柱(4.6×250 mm,5μm),V(0.02 mol/L的磷酸盐缓冲液(pH 3.0))∶V(乙腈)=9∶1为流动相,流速为1 mL/min,检测波长210 nm,柱温为25℃。乙酰半胱氨酸峰与有关物质峰的分离度均大于1.5;乙酰半胱氨酸质量浓度在11~111 mg/L的范围内,具有良好的线性关系,回归方程为A=18.195ρ+0.5229,r=0.9995(n=8);乙酰半胱氨酸的定量限为11 mg/L;最低检测限为0.035μg;进样精密度RSD=0.24%(n=6)。     

Bioanalysis of Naproxen by High Performance Reversed Phase Liquid Chromatography with Photometric and Fluorimetric Detection

Abstract

Methods for the quantitative determination of NAPROXEN and its main metabolite in plasma and urine are described. The separation is based on reversed phase liquid chromatography with LiChrosorb RP 8 (5 μm) as the support and methanol/phosphate buffer pH 7 as mobile phase, in some cases with addition of tetrabutyl ammonium ion as ion-pairing agent to improve the chromatographic selectivity. With UV-detector and a simple filter fluorometer an extraction-evaporation procedure is used for both plasma and urine determinations, while the high selectivity and sensitivity of a sophisticated fluorescence detector permits the direct injection of diluted samples on to the column. Use of an internal standard improves the within-run precision (s_rel%), which for plasma determinations of NAPROXEN are - with UV-detection, 0.2 – 1.7% (range 10 – 40 μg/ml), with filter fluorometer, 2.4 – 5.9% (range 12 – 58 μg/ml), and with fluorescence detector, 0.8 – 4.1% (range 5 – 20 μg/ml).     

Fluorometric determination of khellin in human urine and serum by high-performance liquid chromatography using postcolumn photoirradiation.

For the determination of khellin in urine and serum, fluorometry using HPLC-postcolumn photoirradiation has been developed. Khellin and visnagin of similar structure were separated on a column of Capcell Pak C8. The mobile phase consisted of 40%(v/v) ethanol containing 75 mmol l(-1) H2O2. The postcolumn reagent, 70 mmol l(-1) KH2PO4-NaOH buffer (pH 12.7) containing 50%(v/v) ethanol, were mixed with the mobile phase, which was irradiated with ultraviolet light to induce fluorescence. The fluorescence was monitored with excitation at 378 nm and emission at 480 nm. The calibration graph for khellin was linear over the range of 65 - 2620 ng ml(-1) using an injection volume of 20 microl. The pretreatment of the urine or serum samples consisted of diluting steps or deproteinizing steps using perchloric acid, respectively.     

High-performance liquid chromatographic analysis of a novel carbapenem antibiotic in human plasma and urine

High-performance liquid chromatographic methods for quantification of a novel carbapenem anti-infective agent, I, in plasma and urine have been developed, validated, and applied to clinical samples. The carbapenem is stabilized in the matrix by the addition of a non-nucleophilic buffer, rapid freezing, and storage at -70 degrees C. After addition of another carbapenem, II, as internal standard, plasma proteins are precipitated with acetonitrile, which is subsequently extracted from the sample with methylene chloride. A portion of the aqueous phase is injected onto a reversed-phase phenyl column that is eluted with 4% (v/v) acetonitrile in 15 mM ammonium phosphate (pH 7.4). The urine assay entails addition of the internal standard II to buffered urine, which is subsequently extracted with methylene chloride prior to injection of the aqueous phase onto a cation-exchange column. The urine assay mobile phase is 5% v/v tetrahydrofuran in 100 mM sodium acetate (pH 5.4). The detector response at 313 nm is a linear (r greater than 0.99) function of concentration over the ranges 0.50-100 micrograms/ml and 2.0-200 micrograms/ml for the plasma and urine assays, respectively. Thermal degradation products do not interfere with either assay. These assays have proven to be accurate, precise, reproducible, and rugged during clinical sample analyses.