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Liquid Chromatographic (liquid + chromatographic)
Kinds of Liquid Chromatographic Terms modified by Liquid Chromatographic Selected AbstractsLiquid chromatographic,tandem mass spectrometry assay for quantitation of a novel antidiabetic S002-853 in rat plasma and its application to pharmacokinetic study,BIOMEDICAL CHROMATOGRAPHY, Issue 7 2010N. Gautam Abstract A sensitive and selective LC-MS/MS method has been developed and validated for the estimation of novel antidiabetic synthetic flavonoid S002-853 in rat plasma using centchroman as an internal standard. The method involves a simple two-step liquid,liquid extraction with diethyl ether. The analyte was chromatographed on a Pierce Spheri-5, guard cyano column (30 × 4.6,,mm i.d., 5,,µm) with isocratic mobile phase consisting of methanol,ammonium acetate buffer (pH 4.6, 10,,mm; 90,:,10, v/v) at a flow rate of 0.75,,mL/min. The API 4000 triple-quadrupole LC,MS/MS system was operated under multiple reaction-monitoring mode. The ionization was performed by electrospray ionization technique in positive ion mode. The chromatographic run time was 6,,min and the weighted (1/x2) calibration curves were linear over the range 0.78,400,,ng/mL. The limit of detection and lower limit of quantification were 0.195 and 0.78,,ng/mL, respectively. The intra- and inter-batch accuracy (%bias) and precision (%RSD) were found to be less than 8.47 and 11.6% respectively. The average absolute recoveries of S002-853 and internal standard from spiked plasma samples were >90%. S002-853 was stable for 8,,h at ambient temperature, 4 weeks at ,60°C and after three freeze,thaw cycles. The assay was successfully applied to determine the pharmacokinetic parameters in male Sprague,Dawley rats after an oral dose administration at 25,,mg/kg. Copyright © 2009 John Wiley & Sons, Ltd. [source] Liquid chromatographic assay for the cyclic depsipeptide aplidine, a new marine antitumor drug, in whole blood using derivatization with trans -4,-hydrazino-2-stilbazoleBIOMEDICAL CHROMATOGRAPHY, Issue 1 2004Rolf W. Sparidans Abstract A sensitive bio-analytical assay for the depsipeptide aplidine in plasma has been modi,ed and tested for human whole blood samples. The adapted method is based on reversed-phase liquid chromatography and ,uorescence detection of the trans -4,-hydrazino-2-stilbazole derivative of the analyte. Aplidine is isolated from the matrix by solid-phase extraction on an octadecyl modi,ed silica stationary phase. After evaporation of the acetone eluate, the derivatization with the hydrazino reagent is performed in a water,acetonitrile mixture at pH = 4. The reaction mixture is injected directly into the chromatograph and the analyte is quanti,ed by ,uorescence detection at 410 and 560 nm for excitation and emission, respectively. The method has been validated in the 2,100 ng/mL range, with 2 ng/mL being the lower limit of quanti,cation. Precision and accuracy both meet the current requirements for a bioanalytical assay. The stability of aplidine in whole blood at ambient temperature and at 37°C is limited; recoveries in the range 60,85% were observed after 7 h. Further, adequate stability of aplidine in plasma at ,80 and ,20°C for 35 months could now be demonstrated. Copyright © 2003 John Wiley & Sons, Ltd. [source] Liquid chromatographic,mass spectrometry analysis and pharmacokinetic studies of a novel rabeprazole formulation, sterile powder for injection, in dogs and ratsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 4 2007Feng Shao Abstract Rabeprazole is among the most potent proton pump inhibitors (PPI) identified to date and it has been demonstrated that it is effective in such diseases as gastroesophageal reflux disease (GERD), duodenal ulcer and gastric ulcer. There is currently interest in developing a new formulation: rabeprazole sterile powder for injection (RSPI). This investigation was conducted to evaluate the preclinical pharmacokinetics of RSPI in rats and at the same time a comparative study was carried out in dogs between RSPI and Pariet® tablets using liquid chromatographic,mass spectrometry analysis. The liquid chromatographic,mass spectrometry method was first conducted and validated as being specific, and having accuracy, precision, sensitivity and a satisfactory recovery. After intravenous administration of RSPI (i.v.: 2, 6 and 18 mg/kg) to rats, no significant dose-dependency was found in the CL (4.20,5.72 l/h/kg), Varead (0.94,1.32 l/kg), dose-normalized AUC (197.20,245.82 µg/l*h based on 1 mg/kg) and t1/2 (p>0.05). In the dog, a randomized, open-label, crossover experiment was carried out to show that the mean area under the plasma concentration-time curve (AUC0,,) after i.v. administration of RSPI was at least four times larger than that following oral administration of Pariet® tablet at an equivalent dose but the elimination half-life of these two formulation was similar (p>0.05). The results showed that the pharmacokinetics of RSPI was linear (r2 = 0.98) in the dose range 2,18 mg/kg and the RSPI had a much higher AUC0,, and similar t1/2 values compared with the enteric-coated tablet. Copyright © 2007 John Wiley & Sons, Ltd. [source] Direct injection horse-urine analysis for the quantification and confirmation of threshold substances for doping control.DRUG TESTING AND ANALYSIS, Issue 8 2009Abstract Levodopa and dopamine have been abused as performance-altering substances in horse racing. Urinary 3-methoxytyramine is used as an indicator of dopaminergic manipulation resulting from dopamine or levodopa administration and is prohibited with a urinary threshold of 4 µg mL,1 (free and conjugated). A simple liquid chromatographic (LC)/mass spectrometric (MS) (LCMS) method was developed and validated for the quantification and identification of 3-methoxytyramine in equine urine. Sample preparation involved enzymatic hydrolysis and protein precipitation. Hydrophilic interaction liquid chromatography (HILIC) was selected as a separation technique that allows effective retention of polar substances like 3-methoxytyramine and efficient separation from matrix compounds. Electrospray ionization (ESI) in positive mode with product ion scan mode was chosen for the detection of the analytes. Quantification of 3-methoxytyramine was performed with fragmentation at low collision energy, resulting in one product ion, while a second run at high collision energy was performed for confirmation (at least three abundant ions). Studies on matrix effects showed ion suppression depending on the horse urine used. To overcome the variability of the results originating from the matrix effects, isotopic labelled internal standard was used and linear regression calibration methodology was applied for the quantitative determination of the analyte. The tested linear range was 1,20 µg mL,1. The relative standard deviations of intra- and inter- assay analysis of 3-methoxytyramine in horse urine were lower than 4.2% and 3.2%, respectively. Overall accuracy (relative percentage error) was less than 6.2%. The method was applied to case samples, demonstrating simplicity, accuracy and selectivity. Copyright © 2009 John Wiley & Sons, Ltd. [source] Preparation of normal-phase HPLC stationary phase based on monodisperse hydrophilic polymeric beads and their applicationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Bolin Gong Abstract The monodisperse, 5.0 ,m hydrophilic macroporous poly(glycidymethacrylate- co -ethylenedimethacrylate) beads were first prepared based on monosized linear poly(glycidylmethacrylate) beads as seed by using a single-step swelling and polymerization method. The seed beads prepared by dispersion polymerization exhibited good absorption of the monomer phase. The pore size distribution of the beads was evaluated by mercury instrusion method. The surface area was calculated from the BET isotherms of nitrogen adsorption and desorption. The beads were modified to be a normal-phase liquid chromatographic (NPLC) stationary phase for high performance liquid chromatography (HPLC) in the following steps. First, the beads were completely hydrolyzed. Second, hydrolyzed particles were reacted with epichlorihydrin followed by another hydrolysis of the newly introduced epoxide groups. The retention properties of the NPLC stationary phase were easily modulated by changes in the composition of the mobile phase. The performance of theses beads was demonstrated with the separation of a variety of polar compounds. The satisfactory results were obtained. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] High-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry for the determination of flocoumafen and brodifacoum in whole bloodJOURNAL OF APPLIED TOXICOLOGY, Issue 1 2007Mi-cong Jin Abstract A high-performance liquid chromatographic,tandem mass spectrometric (HPLC,MS,MS) assay was developed and validated to determine quantitatively flocoumafen and brodifacoum in whole blood using warfarin as an internal standard (IS). Liquid,liquid extraction, using ethyl acetate, was used to isolate flocoumafen, brodifacoum and the IS from the biological matrix. Detection was performed on a mass spectrometer by negative electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The calibration curves were linear (r2 > 0.998) in the concentration range of 0.1,100.0 ng ml,1 with a lower limit of quantification of 0.05 ng ml,1 for flocoumafen, and 0.1 ng ml,1 for brodifacoum in whole blood. Intra-day and inter-day relative standard deviations (RSDs) were less than 8.0% and 10.8%, respectively. Recoveries of flocoumafen and brodifacoum ranged from 78.0% to 83.7%. This assay can be used to determine trace flocoumafen and brodifacoum in whole blood to investigate suspected poisoning of human and animals. Copyright © 2006 John Wiley & Sons, Ltd. [source] A simple and rapid high-performance liquid chromatographic (HPLC) method for 5-fluorouracil (5-FU) assay in plasma and possible detection of patients with impaired dihydropyrimidine dehydrogenase (DPD) activityJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 4 2004J. Ciccolini PharmD PhD Summary Background:, Dihydropyrimidine dehydrogenase (DPD) gene polymorphism may lead to severe toxicity with 5-fluorouracil (5-FU), a major anticancer drug extensively used in clinical oncology. Drug monitoring combined with early detection of patients at risk would enable timely dose adaptation so as to maintain drug concentrations within a therapeutic window. However, the best method to identify such patients remains to be determined. Objective:, The aim of this study was to develop a rapid and simple high-performance liquid chromatographic (HPLC) method for estimating uracil/dihydrouracil (U/UH2) ratio in plasma, as an index of DPD status, and for assaying 5-FU as part of drug level monitoring. Method:, Assay of 5-FU, and U/UH2 detection were performed on a HPLC system equipped with UV detector. Analytes were separated at room temperature using a 5 ,m particles, 25 cm RP-18 X-Terra column. The mobile-phase consisted of a KH2PO4 salt solution (0·05 m) + 0·1% triethylamine (TEA) pumped at 0·4 mL/min. Detection of 5-FU and 5-bromouracil were performed at 254 nm; U and UH2 elution was monitored at 210 nm. Results:, The method was sensitive and specific for assaying 5-FU within the 5,500 ng/mL concentration range, which covers exposure levels currently met in clinical practice. The method was simple, and relatively cheap, and rapid, with an analytical run time of about 30 min. Data from a patient with 5-FU toxicity suggest that the method was capable of identifying DPD metabolic phenotype in cancer patients, based on measurement of plasma U/UH2 ratio. Conclusion:, The method described should be suitable both for detecting patients at high risk of 5-FU toxicity, and for drug level monitoring during chemotherapy. [source] Development and validation of a liquid chromatographic/tandem mass spectrometric assay for the quantitation of nucleoside HIV reverse transcriptase inhibitors in biological matricesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2005Séverine Compain Abstract Besides liquid chromatographic (LC)/UV methods adapted to therapeutic drug monitoring, there is still a need for more powerful techniques that can be used for pharmacological research and clinical purposes. We developed an LC method coupled with tandem mass spectrometry (MS/MS) to separate, detect and quantify with high sensitivity the nucleoside analogues used in multitherapies (zidovudine, stavudine, zalcitabine, didanosine, lamivudine and abacavir) in plasma and in the intracellular medium. We worked on two essential issues: (i) the need to use two ionization modes in order to achieve the best sensitivity, which leads to the optimization of the chromatographic separation of drugs detected in the positive ionization mode and drugs detected in the negative ionization mode, and (ii) the need to optimize the extraction step in order to enhance sample recovery. The peripheral blood mononuclear cells were lysed in Tris buffer,MeOH. A clean-up procedure was performed by solid-phase extraction only for plasma samples. The LC separation was carried out on a Zorbax Stable Bond C18 column followed by MS/MS analysis after electrospray ionization in either the negative or positive mode. The positive ionization mode was applied at the beginning of the run to detect zalcitabine and lamivudine, then the ionization mode was changed to negative for the detection of didanosine, stavudine, internal standard and zidovudine. The calibration range for all the analytes was 0.5,200 ng ml,1. The recoveries were between 64 and 90%, with coefficients of variation (CVs) lower than 15%. The inaccuracy (bias) was ±15% with CVs always lower than 12%. The analytes were stable at room temperature and in the extraction solvent for at least 24 h, after storage at ,80 °C for 3 months, after three freeze,thaw cycles and in the injection solvent after 48 h at 4 °C. Together with the measurement of intracellular triphosphorylated metabolites thanks to the powerful plasma and intracellular assay method for intact drugs, it is possible to describe the behaviour of nucleoside analogues against HIV through plasma pharmacokinetics, cell membrane diffusion including drug transport involvement, and also the intracellular metabolism. Copyright © 2005 John Wiley & Sons, Ltd. [source] Gradient HPLC of antibiotics in urine, ground water, chicken muscle, hospital wastewater, and pharmaceutical samples using C-18 and RP-amide columnsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 2 2008Ashwini Kumar Abstract A simple and highly sensitive high pressure liquid chromatographic (HPLC-UV) method has been developed for the determination of ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid, in mobile phase citrate buffer (0.001 M) of pH 4.5 prepared in water (X), methanol (Y), and ACN (Z) using gradient at a flow rate of 1.0 mL/min by direct UV absorbance detection at , = 280 nm. Separation of analytes was studied on the C-18 and RP-amide columns and best results were observed on the RP-amide column with LODs (3.3×S/m) 0.89, 0.55, 0.67, and 1.41 ng/mL for ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid, respectively, and better RSD than the C-18 column. The recovery of Fluoroquinolones (FQs) in urine, ground water, hospital wastewater, and chicken muscle using this method is more than 90%. The method was successfully applied to the analysis of ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid in urine, ground water, pharmaceutical dosage forms, hospital wastewater, and chicken muscle. [source] Fingerprint chromatogram analysis of Pseudostellaria heterophylla (Miq.) Pax root by high performance liquid chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2006Chao Han Abstract A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated for the fingerprinting of extracts from the root of Pseudostellaria heterophylla (Miq.) Pax. HPLC with gradient elution was performed on an authentic reference standard of powdered P. heterophylla (Miq.) Pax root and 11 plant samples of the root were collected from different geographic locations. The HPLC chromatograms have been standardized through the selection and identification of reference peaks and the normalization of retention times and peak intensities of all the common peaks. The standardized HPLC fingerprints show high stability and reproducibility, and thus can be used effectively for the screening analysis or quality assessment of the root or its derived products. Similarity index calculations based on cosine angle values or correlation methods have been performed on the HPLC fingerprints. As a group, the fingerprints of the P. heterophylla (Miq.) Pax samples studied are highly correlated with closely similar fingerprints. Within the group, the samples can be further divided into subgroups based on hierarchical clustering analysis (HCA). Sample grouping based on HCA coincides nicely with those based on the geographical origins of the samples. The HPLC fingerprinting techniques thus have high potential in authentication or source-tracing types of applications. [source] Determination of the purity of ampicillin by micellar electrokinetic chromatography and reversed phase liquid chromatography on a monolithic silica columnJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7-8 2004Milada Dole, alová Abstract A micellar electrokinetic chromatographic (MEKC) method and a fast reversed-phase liquid chromatographic one have been developed for determining the purity of ampicillin. MEKC separation of ampicillin and its related substances was performed with the use of an untreated fused-silica capillary and 40 mM phosphate-borate buffer, pH 7.5 containing 75 mM SDS. The HPLC method employed a monolithic silica C18 column and a mobile phase composed of phosphate buffer, pH 5.2 and ACN, the flow rate being 4.0 mL/min. Both methods were successfully validated. Linearity, relative response factors, limits of quantitation, intermediate precision, and accuracy were evaluated. The methods proved to be fast, reliable, and sufficiently sensitive and, accordingly, well-suited for control of purity of ampicillin substance, injections, and capsules. A combination of both methods can be very useful in the confirmation of impurity profiles. [source] Flavonol glycosides and antioxidant capacity of various blackberry and blueberry genotypes determined by high-performance liquid chromatography/mass spectrometryJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2005Mi Jin Cho Abstract Flavonol glycoside composition and content in blueberry and blackberry extracts were determined using a high-performance liquid chromatographic (HPLC) separation method coupled with photodiode array (PDA) and mass spectrometric (MS) detection. The hydrophilic antioxidant capacities of crude and fractionated flavonol extracts were also determined by the oxygen radical-absorbing capacity (ORACFL) and photochemiluminescence (PCL) assays. Eight flavonols of quercetin and quercetin,sugar conjugates were identified in Kiowa blackberry, namely rutinoside, galactoside, methoxyhexoside, glucoside, pentoside, [6,-(3-hydroxy-3-methylglutaroyl)]-,-galactoside, glucosylpentoside and oxalylpentoside. Thirteen flavonols were detected in Ozarkblue blueberry. Of these, myricetin 3-hexoside and 12 quercetin,sugar conjugates, namely rutinoside, galactoside, methoxyhexoside, glucoside, pentoside, glucosylpentoside, caffeoylglucoside, oxalylpentoside, rhamnoside, dimethoxyrhamnoside, acetylgalactoside and acetylglucoside, were identified. In Bluecrop blueberry, two additional quercetin,sugar conjugates were identified, namely glucuronide and caffeoylgalactoside. Quercetin glycosides accounted for 75% of total flavonols in the blueberry genotypes. Total flavonol contents ranged from 99 to 150 mg kg,1 for blackberries and from 192 to 320 mg kg,1 for blueberries. Quenching of peroxyl and superoxide anion radicals by the flavonol fractions ranged from 1.5 to 2.3 mmol Trolox equivalents (TE) kg,1 and from 0.5 to 0.7 mmol TE kg,1 respectively for blackberries and from 2.9 to 5.2 mmol TE kg,1 and from 0.8 to 1.4 mmol TE kg,1 respectively for blueberries. The HPLC method allowed for complete separation and identification of flavonols commonly found in blackberries, and blueberries. Our results showed that blueberry and blackberry genotypes varied significantly in flavonol content and antioxidant capacity. Even though total flavonol content did not correlate well with antioxidant capacity, their ability to scavenge peroxyl and superoxide anion radicals was apparent. Copyright © 2005 Society of Chemical Industry [source] Use of activated graphitized carbon chips for liquid chromatography/mass spectrometric and tandem mass spectrometric analysis of tryptic glycopeptidesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2009William R. Alley Jr. Protein glycosylation has a significant medical importance as changes in glycosylation patterns have been associated with a number of diseases. Therefore, monitoring potential changes in glycan profiles, and the microheterogeneities associated with glycosylation sites, are becoming increasingly important in the search for disease biomarkers. Highly efficient separations and sensitive methods must be developed to effectively monitor changes in the glycoproteome. These methods must not discriminate against hydrophobic or hydrophilic analytes. The use of activated graphitized carbon as a desalting media and a stationary phase for the purification and the separation of glycans, and as a stationary phase for the separation of small glycopeptides, has previously been reported. Here, we describe the use of activated graphitized carbon as a stationary phase for the separation of hydrophilic tryptic glycopeptides, employing a chip-based liquid chromatographic (LC) system. The capabilities of both activated graphitized carbon and C18 LC chips for the characterization of the glycopeptides appeared to be comparable. Adequate retention time reproducibility was achieved for both packing types in the chip format. However, hydrophilic glycopeptides were preferentially retained on the activated graphitized carbon chip, thus allowing the identification of hydrophilic glycopeptides which were not effectively retained on C18 chips. On the other hand, hydrophobic glycopeptides were better retained on C18 chips. Characterization of the glycosylation sites of glycoproteins possessing both hydrophilic and hydrophobic glycopeptides is comprehensively achieved using both media. This is feasible considering the limited amount of sample required per analysis (<1,pmol). The performance of both media also appeared comparable when analyzing a four-protein mixture. Similar sequence coverage and MASCOT ion scores were observed for all proteins when using either stationary phase. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of electrospray capillary temperature on amide hydrogen exchangeRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2008Stephen J. Coales Amide hydrogen/deuterium (H/D) exchange coupled with proteolysis, high-perfeomance liquid chromatographic (HPLC) separation and mass spectrometry (MS) has become a powerful tool to study protein dynamics in solution. Prior to the execution of H/D exchange experiments, various experimental parameters have to be set, including proteolysis, HPLC, and MS conditions. Here we investigate the effects of electrospray capillary temperature on deuterium retention in backbone amides of various pepsin-generated cytochrome c peptides. Lower capillary temperature generally helps retain more deuterium than higher capillary temperature. When the capillary temperature was 150°C, on average 26% more deuterium was retained than when the capillary temperature was set at 250°C. The effects of capillary temperature varied depending on the ions monitored. There was little difference in deuterium retention among different charge state species of the same peptide at 150°C. However, a lower charge state ion loses more deuterium atoms going from 150°C to 250°C than the corresponding higher charge state species. These results indicate that the capillary temperature should be optimized not only to maximize the signal-to-noise of each ion followed in H/D exchange experiments, but also to minimize the deuterium loss of the ions. Also the loss of deuterium in several ions, especially lower charge state ones, should be monitored in the optimization, as the temperature effects vary among ions and are more significant for lower charge state ions. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simultaneous detection of five different 2-hydroxyethyl-DNA adducts formed by ethylene oxide exposure, using a high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry assayRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 1 2008Elaine M. Tompkins A method has been developed for the simultaneous detection and quantitation of five different 2-hydroxyethyl-DNA (HE-DNA) adducts that could be formed as a result of exposure to ethylene oxide (EO). In addition to the major N7-HE-guanine (N7-HEG) adducts this assay can also measure the less prevalent but potentially more biologically significant N1-HE-2,-deoxyadenosine (N1-HEdA), O6 -HE-2,-deoxyguanosine (O6 -HEdG), N6 -HE-2,-deoxyadenosine (N6 -HEdA) and N3-HE-2,-deoxyuridine adducts (N3-HEdU). The method involves the isolation of HE adducts from the unmodified nucleosides by either neutral thermal hydrolysis or enzymatic digestion, followed by high-performance liquid chromatographic (HPLC) purification, before detection and quantification by liquid chromatography tandem mass spectrometry (LC/MS/MS) using selective reaction monitoring (SRM). The limits of detection were in the range 0.5,25,fmol for each individual adduct, making this one of the most sensitive assays available for the detection of N7-HEG. To illustrate the possible applications of the assay, it has been employed in the measurement of endogenous/background and EO-induced HE adducts in a variety of DNA samples. Copyright © 2007 John Wiley & Sons, Ltd. [source] Utility of porous graphitic carbon stationary phase in quantitative liquid chromatography/tandem mass spectrometry bioanalysis: quantitation of diastereomers in plasmaRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2006Yuan-Qing Xia A major challenge in selecting an appropriate stationary phase for diastereomeric separation is that it is difficult to predict which of the commercially available stationary phases could achieve the required liquid chromatographic (LC) separation. This work describes the selection and evaluation of a porous graphitic carbon (PGC) column coupled with tandem mass spectrometry (MS/MS) for the simultaneous quantitation of an experimental drug candidate (I), its two diastereomeric metabolites (II and III), and its demethylated metabolite (IV) in rat plasma. In addition, we investigated the PGC column for the separation of another drug candidate (VI), its two diastereomeric metabolites (VII and VIII) and its ketone metabolite (IX). The PGC column showed excellent chromatographic resolution for the two diastereomers II and III, as well as for VII and VIII. In contrast, the required resolution for the diastereomers II and III could not be achieved using silica-bonded C18, C30, phenyl, perfluorinated, polar embedded and polar end-capped phases. The PGC column showed ruggedness with excellent reproducibility of retention times, peak symmetry and response over a period of more than 400 injections of a plasma acetonitrile-precipitation extract. Excellent accuracy and precision were achieved, with accuracy of 94,108% and intra- and inter-run precision within 9%. This work indicates that PGC is a valuable addition to the repertoire of LC columns used for quantitative LC/MS/MS bioanalysis, especially where the separation and quantitation of diastereomeric analytes is involved. Copyright © 2006 John Wiley & Sons, Ltd. [source] Capillary liquid chromatography/atmospheric-pressure matrix-assisted laser desorption/ionisation ion trap mass spectrometry: a comparison with liquid chromatography/matrix-assisted laser desorption/ionisation time-of-flight and liquid chromatography/electrospray ionisation quadrupole time-of-flight for the identification of tryptic peptidesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2006Colin S. Creaser The atmospheric-pressure matrix-assisted laser desorption/ionisation quadrupole ion trap (AP-MALDI-QIT) analysis of tryptic peptides is reported following capillary liquid chromatographic (LC) separation and direct analysis of a protein digest. Peptide fragments were identified by peptide mass fingerprinting from mass spectrometric data and sequence analysis obtained by tandem mass spectrometry of the principal mass spectral peaks using a data-dependent scanning protocol. These data were compared with those from mass spectrometric analysis using capillary LC/MALDI-time-of-flight (TOF) and capillary LC/electrospray ionisation (ESI)-quadrupole TOF. For all three configurations the resulting data were searched against the MSDB database, using MASCOT and the sequence coverage compared for each technique. Complementary data were obtained using the three techniques. Copyright © 2006 John Wiley & Sons, Ltd. [source] Closely spaced external standard: a universal method of achieving 5 ppm mass accuracy over the entire MALDI plate in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2003Eugene Moskovets Close deposition of the sample and external standard was used in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to achieve mass accuracy equivalent to that obtained with an internal standard across the entire MALDI plate. In this work, the sample and external standard were deposited by continuous deposition in separate traces, each approximately 200,,m wide. The dependence of the mass accuracy on the distance between the sample and standard traces was determined across a MALDI target plate with dimensions of 57.5,mm,×,57.0,mm by varying the gap between the traces from 100,,m to 4,mm. During acquisition, two adjacent traces were alternately irradiated with a 200-Hz laser, such that the peaks in the resulting mass spectra combined the sample and external standard. Ion suppression was not observed even when the peptide concentrations in the two traces differed by more than two orders of magnitude. The five peaks from the external standard trace were used in a four-term mass calibration of the masses of the sample trace. The average accuracy across the whole plate with this method was 5,ppm when peaks of the sample trace had signal-to-noise ratios of at least 30 and the gap between the traces was approximately 100,,m. This approach was applied to determining peptide masses of a reversed-phase liquid chromatographic (LC) separation of a tryptic digest of , -galactosidase deposited as a long serpentine trace across the MALDI plate, with accuracy comparable to that obtainable using internal calibration. In addition, the eluent from reversed-phase LC separation of a strong cation-exchange fraction containing tryptic peptides from a yeast lysate along with the closely placed external standard was deposited on the MALDI plate. The data obtained in the MS and MS/MS modes on a MALDI-TOF/TOF mass spectrometer were combined and used in database searching with MASCOT. Since the significant score is a function of mass accuracy in the MS mode, database searching with high mass accuracy reduced the number of false positives and also added peptides which otherwise would have been eliminated at lower mass accuracy (false negatives). Copyright © 2003 John Wiley & Sons, Ltd. [source] A sensitive liquid chromatography,electrospray ionization,mass spectrometry method for the simultaneous determination of pentoxyverine citrate and guaifenesin in human plasma,application to pharmacokinetic and bioequivalence studiesBIOMEDICAL CHROMATOGRAPHY, Issue 4 2010Jinhua Wen Abstract A sensitive and specific liquid chromatography,electrospray ionization,mass spectrometry method for the identification and quantification of pentoxyverine citrate and guaifenesin in human plasma has been developed. After extraction from plasma samples by ethyl acetate, the internal standard and analytes were separated by high-performance liquid chromatographic on a Shim-pack VP-ODS C18 column (150 × 2.0 mm) using a mobile phase consisting of A (methanol) and B (0.4% glacial acetic acid and 4 mmol/L ammonium acetate) (A:B, 43 : 57). Analysis was performed on a Shimadzu LC/MS-2010A in selected ion monitoring mode with a positive electrospray ionization interface. The method was linear in the concentration range of 1.0,640.0 ng/mL for pentoxyverine citrate and 0.025,6.4 ,g/mL for guaifenesin. The inter- and intra- precision were all within 12% and accuracy ranged from 85 to 115%. The lower limits of quantification were 1.0 ng/mL for pentoxyverine citrate and 25.0 ng/mL for guaifenesin. The extraction recovery was on average 81.95% for pentoxyverine citrate and 89.03% for guaifenesin. This is the first assay method reported for the simultaneous determination of pentoxyverine citrate and guaifenesin in plasma using one chromatographic run. Copyright © 2009 John Wiley & Sons, Ltd. [source] A simple RP-HPLC method for quantification of columbianadin in rat plasma and its application to pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 4 2010You-Bo Zhang Abstract A rapid and sensitive reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed to investigate pharmacokinetics of columbianadin, one of the main bioactive constituents in the roots of Angelica pubescens f. biserrata, in rat plasma after intravenous administration to rats at two doses of 10 and 20,mg/kg. The method involves a plasma clean-up step using liquid,liquid extraction by diethyl ether, followed by RP-HPLC separation and detection. Separation of columbianadin was performed on an analytical DiamonsilÔ ODS C18 column, with a mobile phase of MeOH,H2O (85,:,15, v/v) at a flow-rate of 1.0,mL/min, and UV detection was set at 325,nm. The retention time of columbianadin and scoparone (internal standard) was 6.7 and 3.5,min, respectively. The calibration curve was linear over the range of 0.2,20.0,,g/mL (r2 = 0.9986) in rat plasma. The lower limits of detection and quantification were 0.05 and 0.1,,g/mL, respectively. The extraction recovery from plasma was in the range of 81.61,89.93%. The intra- and inter-day precisions (relative standard deviation) were between 1.01 and 9.33%, with accuracies ranging from 89.76 to 109.22%. The results indicated that the method established was suitable for the determination and pharmacokinetic study of columbianadin in rat plasma. Copyright © 2009 John Wiley & Sons, Ltd. [source] Simple and sensitive HPLC method for determination of amrubicin and amrubicinol in human plasma: application to a clinical pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 3 2010Reiko Ando Abstract A simple and sensitive high-performance liquid chromatographic (HPLC) method was developed for determination of amrubicin and its metabolite amrubicinol in human plasma. After protein precipitation with methanol without evaporation procedure, large volume samples were injected and separated by two monolithic columns with a guard column. The mobile phase consisted of tetrahydrofuran,dioxane,water (containing 2.3,mM acetic acid and 4,mM sodium 1-octanesulfonate; 2:6:15, v/v/v). Wavelengths of fluorescence detection were set at 480,nm for excitation and 550,nm for detection. Under these conditions, linearity was confirmed in the 2.5,5000,ng/mL concentration range of both compounds. The intra- and inter-day precision and intra- and inter-day accuracy for both compounds were less than 10%. The method was successfully applied to a clinical pharmacokinetic study of amrubicin and amrubicinol in cancer patients. Copyright © 2009 John Wiley & Sons, Ltd. [source] A simple and rapid high-performance liquid chromatography method for determination of alendronate sodium in beagle dog plasma with application to preclinical pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 2 2010Jian Meng Abstract A simple and rapid high performance liquid chromatographic (HPLC) method for quantifying alendronate in beagle dog plasma was developed, validated and applied to a pharmacokinetic study. The sample preparation involved coprecipitation with CaCl2 and derivatization with o -phthalaldehyde. Chromatographic separation was achieved on a DiamonsilÔ C18 (250 × 4.6,mm, 5,µm) using acetonitrile,0.4% EDTA-Na2 (16:84, v/v) containing 0.034% of NaOH as mobile phase. The fluorimetric detector was operated at 339,nm (excitation) and 447 nm (emission). The linearity over the concentration range of 5.00,600,ng/mL for alendronate was obtained and the lower limit of quantification was 5.00,ng/mL. For each level of quality control samples, inter-day and intra-day precisions were less than 8.52 and 7.42% and accuracies were less than 9.07%. The assay was applied to the analysis of samples from a pharmacokinetic study. Following the oral administration of 70,mg alendronate sodium to beagle dogs, the maximum plasma concentration (Cmax) and elimination half-life were 152,±,27.3 and 1.75,± 0.267,h, respectively. The method was demonstrated to be highly feasible and reproducible for pharmacokinetic studies. Copyright © 2009 John Wiley & Sons, Ltd. [source] Quality control of PET radiopharmaceuticals by high-performance liquid chromatography with tris(2,2,-bipyridyl)ruthenium(II) electrogenerated chemiluminescence detectionBIOMEDICAL CHROMATOGRAPHY, Issue 2 2010Ryuji Nakao Abstract A highly sensitive reversed-phase liquid chromatographic (HPLC) method was investigated to analyze a range of positron emission tomography (PET) radiopharmaceuticals using electrogenerated chemiluminescence (ECL) detection. ECL is based on the reaction of PET molecules with tris(2,2,-bipyridyl)ruthenium(III) [Ru(bpy)33+], which is generated through the on-line electro-oxidation of Ru(bpy)32+. In 21 different radiopharmaceuticals studied, 18 compounds could be detected with detection limits (signal-to-noise ratio = 3) of 0.12,72 ng/mL per 20 ,L injection. Sufficient reproducibility and linearity were obtained for the quantitative determination of PET molecules in pharmaceutical fluid. This method could be successfully applied to quality control tests of PET radiopharmaceuticals with ultra-high specific radioactivity. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characterization and determination of chlorophacinone in plasma by ion chromatography coupled with ion trap electrospray ionization mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 5 2009Xiao-kun OuYang Abstract Plasmatic chlorophacinone is commonly measured with liquid chromatographic assay, which convenient but lacks sensitivity and selectivity and usually requires ion pair reagents to reduce the chromatographic tailed peak. In this paper, a novel method using eluent generator reagent-free ion chromatography coupled with electrospray ionization ion trap mass spectrometric detection for the determination of chlorophacinone in plasma has been developed. After samples were extracted with 10% (v/v) methanol in acetonitrile and cleaned by solid-phase extraction, chromatographic separation was performed on an IonPac® AS11 analytical column (250 × 4.0 mm) using 40.0 mmol/L KOH containing 10% (v/v) methanol as organic modifier. Quantification was performed by negative electrospray ionization in multiple reaction monitoring mode. The transition m/z 373 , 201 was for the quantification ion; the transitions m/z 373 , 172 and m/z 373 , 145, as well as the isotope ions m/z 375 and m/z 203, were for the qualitative ions. All the method parameters were validated. It was confirmed that this method can be used in clinical diagnosis and forensic toxicology. Copyright © 2008 John Wiley & Sons, Ltd. [source] High-performance liquid chromatography and LC-ESI-MS method for the identification and quantification of two biologically active isomeric coumarinolignoids cleomiscosin A and cleomiscosin B in different extracts of Cleome viscosaBIOMEDICAL CHROMATOGRAPHY, Issue 12 2008Sunil K. Chattopadhyay Abstract A rapid, sensitive and simple reverse-phase high-performance liquid chromatographic,electrospray ionization,mass spectrometry method for simultaneous determination of cleomiscosin A and cleomiscosin B has been developed and validated. The isomeric coumarinolignoids cleomiscosin A (1) and cleomiscosin B (2) were separated on a Waters symmetry C18 column with a solvent system composed of acetonitrile,methanol (1:2) and acetic acid,water (0.5 : 99.5) in a gradient elution mode. The absorption at 326 nm was chosen as the measuring wavelength in which resolution and baseline separation of compounds 1 and 2 could be obtained. The identity of the two isomeric compounds 1 and 2 in the samples were determined on a triple quadrupole mass spectrometer with ESI interface operating in the positive mode. Calibration curves were linear (r2 > 0.993) over the concentration range 20,200 µg/mL for cleomiscosin A and 10,200 µg/mL for cleomiscosin B with acceptable accuracy and precision, respectively. The intra-day and inter-day precision were 1.13 and 0.82% for cleomiscosin A and 1.78 and 1.28% for cleomiscosin B, respectively. The validated method was successfully applied for the analysis of the above two compounds in different extracts of Cleome viscosa. Copyright © 2008 John Wiley & Sons, Ltd. [source] An HPLC method for the determination and pharmacokinetic study of lehmannine in rat plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 10 2008Gang Zhao Abstract A high-performance liquid chromatographic (HPLC) method for determining lehmannine (LMN) in rat plasma was developed for application in the pharmacokinetics study. The plasma was deproteinized with acetonitrile that contained an internal standard and was separated from the aqueous layer by adding sodium chloride. The HPLC assay was carried out using a VP-ODS column at 40°C. The mobile phase was acetonitrile,0.02 mol/L ammonium acetate buffer,triethylamine (35:65:0.04, v/v/v). The flow rate was 1.0 mL/min. The detection wavelength was set at 220 nm. The method was used to determine the concentration,time profiles of LMN in the plasma following oral administration or bolus injection of LMN aqueous solution. The pharmacokinetic parameters of LMN were calculated for the first time by Drug and Statistics 1.0 program. Copyright © 2008 John Wiley & Sons, Ltd. [source] A stereospecific high-performance liquid chromatographic assay for the determination of ketoconazole enantiomers in rat plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 5 2008Dalia A. Hamdy Abstract A stereospecific high-performance liquid chromatographic assay was developed for the quantitation of ketoconazole enantiomers (KTZ) in rat plasma. After protein precipitation of 100 µL plasma using acetonitrile, a wash step was performed using hexane. The supernatant was removed and KTZ enantiomers and amiodarone, the internal standard, were extracted using liquid,liquid extraction with tert-butyl methyl ether. After transfer and evaporation of the organic layer, the residue was reconstituted in mobile phase and injected into the HPLC through a chiral column. The mobile phase consisted of hexane:ethanol:2-propanol with diethyl amine, pumped at 1.5 mL/min. All components eluted within 18 min. KTZ enantiomers were baseline resolved and peaks were symmetrical in appearance with no interferences. Calibration curves were linear over the range 62.5,5000 ng/mL of enantiomer. The intraday and interday CV% assessments were ,19 and <13%, respectively, and mean error was <4% for both enantiomers. The lower limit of quantitation was 62.5 ng/mL for each enantiomer based on 100 µL rat plasma. In rats, plasma concentrations of (+)-KTZ were higher than those of antipode after single oral doses. The assay was shown to be sensitive and appropriate for use in pharmacokinetics study of KTZ in rat. Copyright © 2008 John Wiley & Sons, Ltd. [source] Reversed-phase high-performance liquid chromatographic, size exclusion chromatographic and polyacrylamide gel electrophoretic studies of glycinin: evidence for molecular species and their association,dissociationBIOMEDICAL CHROMATOGRAPHY, Issue 12 2007Ravi Bhushan Abstract Isolation and purification of glycinin and its molecular species from an Indian soybean variety (JS-335) was achieved using polyacrylamide gel electrophoresis (PAGE), size exclusion chromatography (SEC) and reversed-phase high-performance liquid chromatography (RP-HPLC). Glycinin was found to have two molecular species (glycinin I and II), and only glycinin I underwent reversible dissociation,association system into , and , species. Glycinin I and II were not found to constitute a dissociation,association system. Glycinin II also did not dissociate under varying conditions of time, pH and ionic strength of buffer. Various species so dissociated were isolated, purified and characterized. Copyright © 2007 John Wiley & Sons, Ltd. [source] Determination of imatinib mesylate and its main metabolite (CGP74588) in human plasma and murine specimens by ion-pairing reversed-phase high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 7 2007Roos L. Oostendorp Abstract A sensitive reversed-phase high-performance liquid chromatographic (HPLC) method has been developed and validated for the determination of imatinib, a tyrosine kinase inhibitor, and its main metabolite N -desmethyl-imatinib (CGP74588) in human plasma and relevant murine biological matrices. A simple HPLC assay for the individual quantification of imatinib and CGP74588 in murine specimens has not been reported to date. Sample pre-treatment involved liquid,liquid extraction with tert -butyl-methyl ether. Imatinib, CGP74588 (metabolite) and the internal standard 4-hydroxybenzophenone were separated using a narrow bore (2.1 × 150 mm) stainless steel Symmetry C18 column and detected by UV at 265 nm. The mobile phase consisted of 28% (v/v) acetonitrile in 50 mm ammonium acetate buffer pH 6.8 containing 0.005 m 1-octane sulfonic acid and was delivered at 0.2 mL/min. The calibration curve was prepared in blank human plasma and was linear over the dynamic range 10 ng/mL to 10 µg/mL). The accuracy was close to 100% and the within-day and between-day precisions were within the generally accepted 15% range. The validation results showed that the assay was selective and reproducible. This method was applied to study the pharmacokinetics of imatinib and its main metabolite in human and mice. Copyright © 2007 John Wiley & Sons, Ltd. [source] Simple determination of huperzine A in human plasma by liquid chromatographic,tandem mass spectrometric methodBIOMEDICAL CHROMATOGRAPHY, Issue 1 2007Yun-Xia Li Abstract Huperzine A is a potent, reversible acetylcholinesterase inhibitor. In the present work, a rapid and sensitive LC,MS,MS method for the determination of huperzine A in human plasma using codeine phosphate as internal standard has been developed and validated. The analyte and internal standard were extracted from plasma using ethyl acetate, chromatographed on a C18 column (5 µm, 150 × 4.6 mm i.d.) with a mobile phase consisting of 1% formic acid,methanol (40:60, v/v), and detected using a tandem mass spectrometer with a TurboIonSpray ionization interface. The run time was only 2 min. Good linearity was achieved in the range 0.126 -25.2 ng/mL and the limit of detection in plasma was 0.064 ng/mL. The average recovery for huperzine A was 83.4% from plasma. The analytical sensitivity and accuracy of this assay is adequate for characterization of huperzine A in human plasma. Copyright © 2006 John Wiley & Sons, Ltd. [source] | |||||||||||||