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Linear Calibration Curve (linear + calibration_curve)
Selected AbstractsConstruction and Evaluation of a Gold Tubular Electrode for Flow Analysis: Application to Speciation of Antimony in Water SamplesELECTROANALYSIS, Issue 6 2007Rodrigo Santos Abstract A tubular gold electrode (TGE) is described for the first time by summarizing the important aspects of its construction and evaluation. Applicability of the TGE is evaluated in the speciation of Sb(III) and Sb(V) using anodic stripping voltammetry in a single flow manifold. Studies with surface active interferences and metallic cations were performed. The proposed conditions for antimony determination showed good tolerance towards cationic, anionic and nonionic surface active substances. A linear response for antimony was obtained for solutions containing significant amounts of several metallic cations. Linear calibration curves for Sb(III) were obtained in the range 1,10,ppb with a detection limit of 0.19,ppb (CV=2.91%, n=5, [Sb(III)]=5,ppb). For Sb(V), linear calibration curves were in the range 1,15,ppb with a detection limit of 0.32,ppb (CV=1.41%, n=5, [Sb(V)]=5,ppb). The figures of merit achieved sustain for the good applicability of the proposed method as it allows the determination of antimony at levels below maximum values permitted in consuming waters. Results of antimony concentration determined in water samples were validated against the ICP-MS reference procedure or compared with reference water samples. [source] Instrumental planar chromatographic method for determination of carbamazepine in human serumJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2009Sigrid Mennickent Abstract An instrumental planar chromatographic (HPTLC) method for quantification of carbamazepine in human serum was developed using liquid-liquid extraction with dichloromethane, fluorescence activation with perchloric acid 60%/ethanol/water (1:1:1, v/v) and fluorescence detection. Planar chromatographic separation was performed on precoated silica gel F254 HPTLC plates using a mixture of ethyl acetate/toluene/methanol/acetic acid glacial (5:4:0.5:0.5, v/v) as mobile phase. Densitometric detection was done at 366 nm. The method was validated for linearity, precision and accuracy. Linear calibration curves in the range of 3 and 20 ng/,L showed correlation coefficient of 0.998. The intra-assay and inter-assay precision, expressed as the RSD, were in the range of 0.41,1.24% (n = 3) and 2.17,3.17% (n = 9), respectively. The LOD was 0.19 ng, and the LOQ was 0.57 ng. Accuracy, calculated as percentage recovery, was between 98.98 and 101.96%, with a RSD not higher than 1.52%. The method was selective for the active principle tested. In conclusion, the method is useful for quantitative determination of carbamazepine in human serum. [source] High-performance liquid chromatography determination of nitrated polycyclic aromatic hydrocarbons by indirect fluorescence detectionBIOMEDICAL CHROMATOGRAPHY, Issue 2 2009Salma M. Al-Kindy Abstract A high-performance liquid chromatography (HPLC) method for the analysis of nitrated polcyclic aromatic hydrocarbons (NPAHs) is reported. NPAH mixtures were pre-concentrated using solid-phase extraction and well resolved on a C18 column. They were detected using an indirect method involving the quenching of the emission from the fluorophores 5,6,7,8-tetrahydronaphthol (5,6,7,8-THN-1-OH), 7-amino-4-methyl coumarin (Coumarin 120, COU-120) and 3-hydroxy-4-(2-hydroxy-4-sulfo-1-naphthylazo)2-naphthalene carboxylic acid (Calcon carboxylic acid, CCA). Linear calibration curves were obtained in the range 1.1 × 10,9 to 1.1 × 10,8 mol/L. Using COU 120 as the fluorophore, the detection limit was 2.9 × 10,10 mol/L for 1-nitronaphthalene and 2.1 × 10,11 mol/L for 2-nitrofluorene. Recoveries of NPAHs from spiked tap water samples were between 88 and 100%. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simultaneous determination and pharmacokinetic study of oxymatrine and matrine in beagle dog plasma after oral administration of Kushen formula granule, oxymatrine and matrine by LC-MS/MSBIOMEDICAL CHROMATOGRAPHY, Issue 8 2007Yiqi Wang Abstract A rapid, specific and sensitive LC-MS/MS method was developed for the determination of oxymatrine (OMT) and matrine (MT) in beagle dog plasma. The method was applied to study the pharmacokinetics of OMT and MT after oral administration of OMT, MT and Kushen formula granule (KFG) containing equivalent amounts of OMT and MT in a three-period crossover design. The analysis was carried out on an Acquity UPLCÔ BEH C18 column by linear gradient elution with 0.01% acetic acid,water,methanol as mobile phase. Detection was by positive ion electrospray ionization (ESI) mass spectrometry with multiple-reaction monitoring (MRM). Linear calibration curves were both obtained over the concentration range 15,2000 ng/mL, with a limit of quantification of 15 ng/mL. The matrix effect was minimized. The intra- and inter-day precisions (RSDs) were less than 12.4 and 14.7%, respectively, and the accuracy (RE) was from ,2.1 to 2.7%. The validated method was used to determine the concentration,time profiles of OMT and MT. The results indicated that the absorption of OMT and MT after oral administration of KFG was significantly greater than that after oral administration of pure components. Copyright © 2007 John Wiley & Sons, Ltd. [source] Voltammetric Detection of Lead(II) Using Amide-Cyclam- Functionalized Silica-Modified Carbon Paste ElectrodesELECTROANALYSIS, Issue 15 2009Stéphanie Goubert-Renaudin Abstract 2-(4,8,11-Triscarbamoylmethyl-1,4,8,11-tetraazacyclotetradec-1-yl)acetamide (TETAM) derivatives bearing 1, 2, or 4 silylated arms have been synthesized and grafted to the surface of silica gel and ordered mesoporous silica samples. The resulting organic-inorganic hybrids have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Pb(II). The attractive recognition properties of these cyclam derivatives functionalized with amide pendent groups toward Pb(II) species and the highly porous structure of the adsorbents can be exploited for the selective and sensitive detection of the target analyte. Various parameters affecting the preconcentration and detection steps have been discussed with respect to the composition and pH of both accumulation and detection media, the nature of the adsorbent (number of silylated groups linking the macrocycle to silica, texture of materials), the accumulation time, and the presence of interfering cations. Under optimal conditions and for 2,min accumulation at open-circuit, the voltammetric response increased linearly with the Pb(II) concentration in a range extending from 2×10,7 to 10,5,M, while a longer accumulation time of 15,min afforded a linear calibration curve between 10,8 and 10,7,M with a detection limit of 2.7×10,9,M which is well below the European regulatory limit of lead in consumption water. [source] Ticlopidine quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry.JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 12 2004Application to bioequivalence study Abstract A rapid, sensitive and specific method to quantify ticlopidine in human plasma using clopidogrel as the internal standard (IS) is described. The analyte and the IS were extracted from acidified plasma by liquid,liquid extraction using diethyl ether,hexane (80 : 20, v/v). The extracts were analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry (HPLC/MS/MS). Chromatography was performed isocratically on a Jones Genesis C8 4 µm analytical column (150 × 4.1 mm i.d.). The method had a chromatographic run time of 3.0 min and a linear calibration curve over the range 1.0,1000 ng ml,1 (r2 > 0.999427). The limit of quantification was 1.0 ng ml,1. This HPLC/MS/MS procedure was used to assess the bioequivalence of two ticlopidine 250 mg tablet formulations (ticlopidine test formulation from Apotex do Brasil, Brazil, and Ticlid from Sanofi-Synthelabo, standard reference formulation). A single 250 mg dose of each formulation was administered to healthy volunteers. The study was conducted using an open, randomized, two-period crossover design with a 2 week washout interval. Since the 90% confidence interval for Cmax and area under the curve ratios were all inside the 80,125% interval proposed by the US Food and Drug Administration, it was concluded that ticlopidine formulation from Apotex do Brasil is bioequivalent to Ticlid formulation with respect to both the rate and the extent of absorption. Copyright © 2004 John Wiley & Sons, Ltd. [source] Automated determination of venlafaxine in human plasma by on-line SPE-LC-MS/MS.JOURNAL OF SEPARATION SCIENCE, JSS, Issue 4 2009Application to a bioequivalence study Abstract A new automated SPE-LC-ESI-MS/MS method was developed and validated to quantify venlafaxine in human plasma using fluoxetine as an internal standard. The analytes were automatically extracted from plasma by C18 SPE cartridges, separated on a C8 RP column and analyzed by MS in the multiple reaction-monitoring (MRM) mode. The method has a chromatographic run time of 4.0 min and a linear calibration curve over the range of 0.25,200 ng/mL (r >0.997). The between-run precisions, based on the percent RSD for replicate quality controls (0.75; 80, and 200 ng/mL), were < 8.5% for all concentrations. The between-run accuracies, based on the percent relative error, were < 4.0%. This method was successfully employed in a bioequivalence study of two venlafaxine capsule formulations (test formulation from Eurofarma (Brazil) and Efexor XR, reference formulation, from Wyeth-Whitehall, Brazil) in 48 healthy volunteers of both sexes who received a single 150 mg dose of each formulation. More than 3000 samples were analyzed eliminating the analyst's exposure to hazardous organic solvents normally employed in off-line liquid,liquid extractions. The 90% confidence interval (CI) of the individual ratio geometric mean for Test/Reference was 91.6,103.4% for AUC0,48 h and 102.2,112.6% for Cmax. Since both 90% CI for AUC0,48 h and Cmax were included in the 80,125% interval proposed by the US Food and Drug Administration (FDA) and the Brazilian National Health Surveillance Agency (ANVISA), the test formulation was considered bioequivalent to Efexor XR according to both the rate and extent of absorption. [source] Characterization of Ethylene-1-Hexene Copolymers Made with Supported Metallocene Catalysts: Influence of Support TypeMACROMOLECULAR SYMPOSIA, Issue 1 2007Beatriz Paredes Abstract Summary: It is known that the nature of the support, as well as the technique used to anchor the metallocene onto it, play important roles on catalytic activity and on the properties of the polymers produced with supported metallocenes. In the present work, the effect of different support types on the microstructure of ethylene/1-hexene copolymers made with supported metallocene catalysts has been investigated through the analysis of molecular weight and chemical composition distributions using high temperature gel permeation chromatography (GPC) and crystallization analysis fractionation (Crystaf). The copolymer samples obtained using commercial carriers (silica and silica-alumina) had unimodal chemical composition distributions and were used to create a linear calibration curve relating the peak crystallization temperature from Crystaf and the comonomer content as determined by 13C NMR. This calibration curve is useful to determine the 1-hexene fractions for each peak in the resins showing bimodal chemical composition distributions, such as those obtained with catalysts supported on MCM-41 and SBA-15 materials. The structure and chemistry of the support used had a large influence on comonomer incorporation and the shape of the chemical composition distribution of the polymer, which suggests that the supporting process creates different types of active sites. [source] Determination of urinary S -phenylmercapturic acid, a specific metabolite of benzene, by liquid chromatography/single quadrupole mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2005Luciano Maestri A high-performance liquid chromatography/single quadrupole mass spectrometry (LC/MS) method is described for the determination of urinary S -phenylmercapturic acid (S-PMA), a specific metabolite of benzene. Urine samples were spiked with [13C6]S-PMA (used as the internal standard) and acidified; then they were purified by solid-phase extraction (SPE) on C18 cartridges. Analyses were conducted on a reversed-phase column by gradient runs with 1% aqueous acetic acid/methanol mixtures at different proportions as the mobile phase. The detector was used in electrospray negative ion mode (ESI,), the ions m/z 238 for S-PMA and 244 for [13C6]S-PMA being recorded simultaneously. The detection limit (for a signal-to-noise ratio,=,3) was 0.2,,g/L, thus allowing for the measurement of background excretion of S-PMA in the general population. The use of the internal standard allowed us to obtain good precision (CV% values <3%) and a linear calibration curve within the range of interest for monitoring occupational exposure to benzene (up to 500,,g/L). The method was applied to assay the metabolite concentration in a group of 299 workers (68 smokers and 231 non-smokers) occupationally exposed to relatively low levels of benzene (environmental concentration,=,0.4,220,,g/m3, mean 11.4,,g/m3) and 236 non-exposed subjects (134 smokers and 102 non-smokers). The results clearly showed that smoking must be taken into account for the correct interpretation of the results of S-PMA measurements for the assessment of work-related benzene exposure. When only non-smokers were selected, the mean excretion of S-PMA was significantly higher in workers exposed to benzene (1.2,±,0.9,,g/g creatinine) than in the control group (0.7,±,0.6,,g/g creatinine) (p,<,0.001), thus confirming the role of S-PMA as a biomarker of benzene on a group basis, even for relatively low exposure degrees. Copyright © 2005 John Wiley & Sons, Ltd. [source] Determination of chlorpheniramine in human plasma by HPLC-ESI-MS/MS: application to a dexchlorpheniramine comparative bioavailability studyBIOMEDICAL CHROMATOGRAPHY, Issue 7 2010Ronilson Agnaldo Moreno Abstract In the present study a fast, sensitive and robust validated method to quantify chlorpheniramine in human plasma using brompheniramine as internal standard (IS) is described. The analyte and the IS were extracted from plasma by LLE (diethyl ether,dichloromethane, 80:20, v/v) and analyzed by HPLC-ESI-MS/MS. Chromatographic separation was performed using a gradient of methanol from 35 to 90% with 2.5,mm NH4OH on a Gemini Phenomenex C8 5,,m column (50 × 4.6,mm i.d.) in 5.0,min/run. The method fitted to a linear calibration curve (0.05,10,ng/mL, R > 0.9991). The precision (%CV) and accuracy ranged, respectively: intra-batch from 1.5 to 6.8% and 99.1 to 106.6%, and inter-batch from 2.4 to 9.0%, and 99.9 to 103.1%. The validated bioanalytical procedure was used to assess the comparative bioavailability in healthy volunteers of two dexchlorpheniramine 2.0,mg tablet formulations (test dexchlorpheniramine, Eurofarma, and reference Celestamine®, Schering-Plough). The study was conducted using an open, randomized, two-period crossover design with a 2 week washout interval. Since the 90% confidence interval for Cmax and AUC ratios were all within the 80,125% interval proposed by ANVISA and FDA, it was concluded that test and reference formulations are bioequivalent concerning the rate and the extent of absorption. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of teniposide in rat plasma by ultra performance liquid chromatography electrospray ionization tandem mass spectrometry after intravenous administrationBIOMEDICAL CHROMATOGRAPHY, Issue 9 2009Jing Wang Abstract A novel, specific and rapid ultra performance liquid chromatography electrospray ionization tandem mass spectrometry method has been developed and validated for determination of teniposide in rat plasma. A one-step liquid,liquid extraction method was used and the separation was carried out on an Acquity UPLCTM BEH C18 column with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.20 mL/min. A triple quadrupole tandem mass spectrometer in multiple-reaction monitoring mode via an electrospray ionization interface was used for the detection of teniposide. The detection was complete within 3.0 min. A linear calibration curve was obtained over the concentration range 10,10,000 ng/mL for teniposide, with a lower limit of quantification of 10 ng/mL. The intra-day precision and inter-day precision (relative standard deviation) were less than 10.23 and 13.09%, respectively. The developed method was applied for the first time to the pharmacokinetic study of teniposide in rats following a single intravenous administration of 4.5 mg/kg teniposide. Copyright © 2009 John Wiley & Sons, Ltd. [source] Fluorescence determination of N -acetylaspartic acid in the rat cerebrum homogenate using high-performance liquid chromatography with pre-column fluorescence derivatizationBIOMEDICAL CHROMATOGRAPHY, Issue 1 2008Takeshi Fukushima Abstract N -Acetyl- l -aspartic acid (NAA) is an endogenous compound, and its brain concentration is suggested to be altered in neurological disorders. In the present study, a fluorescence determination method for NAA was developed by employing reversed-phase high-performance liquid chromatography (HPLC) with pre-column fluorescence derivatization using 4- N,N -dimethylaminosulfonyl-7- N -(2-aminoethyl)amino-2,1,3-benzoxadiazole (DBD-ED). Using methylsuccinic acid as the internal standard, a linear calibration curve for NAA was constructed in the range 125,1000 µm (n = 3). The detection limit on the column was approximately 5.0 fmol (signal-to-noise ratio 3). The proposed HPLC method was applied to determine NAA in the rat cerebrum homogenate. Cerebrum NAA was successfully determined using 10 µL of the homogenate, and the validation data for the proposed HPLC method demonstrated satisfactory results. Intra- and inter-day precision and accuracy were within 1.1,7.0 and ,8.1,6.3%, respectively. The concentration of NAA in the male rat cerebrum (13 weeks old) was 84 ± 4.6 µmol/mg protein (n = 3). Copyright © 2007 John Wiley & Sons, Ltd. [source] Simultaneous Determination of Trace Zinc(II) and Cadmium(II) by Differential Pulse Anodic Stripping Voltammetry Using a MWCNTs,NaDBS Modified Stannum Film ElectrodeELECTROANALYSIS, Issue 23 2009Qing Tian Abstract A multiwalled carbon nanotubes,sodium dodecyl benzene sulfonate (MWCNTs,NaDBS) modified stannum film electrode was employed for the determination of cadmium(II) and zinc(II). The Sn/MWCNTs-NaDBS film electrode was prepared by applying MWCNTs,NaDBS suspension to the surface of the GCE, while the Sn film was plated in situ simultaneously with the target metal ions. Under optimal conditions, linear calibration curves were obtained in a range of 5.0 ,100.0,,g L,1 with detection limits of 0.9,,g L,1 for zinc(II) and 0.8,,g L,1 for cadmium(II), respectively. This film electrode was successfully applied to the determination of Zn(II) and Cd(II) in tap water sample. [source] Quantitative Analysis of Prometrine Herbicide by Liquid,Liquid Extraction Procedures Coupled to Electrochemical MeasurementsELECTROANALYSIS, Issue 6 2009V. Juarez Abstract A sensitive method is proposed for the preconcentration and quantification of the herbicide Prometrine (PROM) at a liquid-liquid interface employing square-wave voltammetry. The preconcentration stage was based on liquid-liquid extraction methodology and the PROM quantification was carried out from the peak current of square-wave voltammograms. Under the experimental conditions employed, linear calibration curves in the concentration range 1.0×10,6,M,5.0×10,5,M, with detection limit equal to 1.5×10,6,M were obtained without pretreatment of the samples. This linear range, as well as detection limit could be extended towards lower concentrations when a pretreatment procedure was employed. In this way, linearity of calibration curves between 8.0×10,8,M and 2.4×10,7,M and detection limit of 1.0×10,7,M, were observed. On the other hand, the standard addition method was also used as an alternative and an appropriated quantification technique for this system. A linear concentration range between 1.0×10,6,M and 2.7×10,5,M, with a correlation coefficient of 0.997, was obtained. This procedure has also a promising application in the separation of herbicides from other interferents, present in real samples, previous to their quantification. [source] Construction and Evaluation of a Gold Tubular Electrode for Flow Analysis: Application to Speciation of Antimony in Water SamplesELECTROANALYSIS, Issue 6 2007Rodrigo Santos Abstract A tubular gold electrode (TGE) is described for the first time by summarizing the important aspects of its construction and evaluation. Applicability of the TGE is evaluated in the speciation of Sb(III) and Sb(V) using anodic stripping voltammetry in a single flow manifold. Studies with surface active interferences and metallic cations were performed. The proposed conditions for antimony determination showed good tolerance towards cationic, anionic and nonionic surface active substances. A linear response for antimony was obtained for solutions containing significant amounts of several metallic cations. Linear calibration curves for Sb(III) were obtained in the range 1,10,ppb with a detection limit of 0.19,ppb (CV=2.91%, n=5, [Sb(III)]=5,ppb). For Sb(V), linear calibration curves were in the range 1,15,ppb with a detection limit of 0.32,ppb (CV=1.41%, n=5, [Sb(V)]=5,ppb). The figures of merit achieved sustain for the good applicability of the proposed method as it allows the determination of antimony at levels below maximum values permitted in consuming waters. Results of antimony concentration determined in water samples were validated against the ICP-MS reference procedure or compared with reference water samples. [source] Chemiluminescence determination of chlorpheniramine using tris(1,10-phenanthroline),ruthenium(II) peroxydisulphate system and sequential injection analysisLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 1 2009Fakhr Eldin O. Suliman Abstract A sequential injection (SI) method was developed for the determination of chlorpheniramine (CPA), based on the reaction of this drug with tris(1,10-phenanthroline),ruthenium(II) [Ru(phen)32+] and peroxydisulphate (S2O82,) in the presence of light. The instrumental set-up utilized a syringe pump and a multiposition valve to aspirate the reagents [Ru(phen)32+ and S2O82,] and a peristaltic pump to propel the sample. The experimental conditions affecting the chemiluminescence reaction were systematically optimized, using the univariate approach. Under the optimum conditions linear calibration curves of 0.1,10 µg/ml were obtained. The detection limit was 0.04 µg/ml and the relative standard deviation (RSD) was always < 5%. The procedure was applied to the analysis of CPA in pharmaceutical products and was found to be free from interferences from concomitants usually present in these preparations. Copyright © 2008 John Wiley & Sons, Ltd. [source] High-throughput determination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry: application to a bioequivalence study of two formulations in healthy volunteersRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2006Hui-chang Bi A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to determine carbocysteine in human plasma was developed and fully validated. After methanol-induced protein precipitation of the plasma samples, carbocysteine was subjected to LC/MS/MS analysis using electrospray ionization (ESI). The MS system was operated in the selected ion monitoring (SRM) mode. Chromatographic separation was performed on a Hypurity C18 column (i.d. 2.1,mm,×,50,mm, particle size 5,µm). The method had a chromatographic running time of 2.0,min and linear calibration curves over the concentration ranges of 0.1,20,µg/mL for carbocysteine. The lower limit of quantification (LLOQ) of the method was 0.1,µg/mL for carbocysteine. The intra- and inter-day precision was less than 7% for all quality control samples at concentrations of 0.5, 2.0, and 10.0,µg/mL. These results indicate that the method was efficient with a simple preparation procedure and a very short running time (2.0,min) for carbocysteine compared with methods reported in the literature and had high selectivity, acceptable accuracy, precision and sensitivity. The validated LC/MS/MS method has been successfully used to a bioequivalence study of two tablet formulations of carbocysteine in healthy volunteers. Copyright © 2006 John Wiley & Sons, Ltd. [source] Simultaneous determination of mifepristone and monodemethyl-mifepristone in human plasma by liquid chromatography,tandem mass spectrometry method using levonorgestrel as an internal standard: application to a pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 1 2009Cheng Tang Abstract A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine mifepristone and monodemethyl-mifepristone in human plasma using levonorgestrel as the internal standard (IS). After solid-phase extraction of the plasma samples, mifepristone, monodemethyl-mifepristone and the IS were subjected to LC-MS/MS analysis using electro-spray ionization (ESI) in the multiple reaction monitoring (MRM) mode. Chromatographic separation was performed on an XTERRA MS C18 column (150 × 2.1 mm i.d., 5 µm). The method had a chromatographic run time of 4.5 min and linear calibration curves over the concentration ranges of 5,2000 ng/mL for mifepristone and monodemethyl-mifepristone. The recoveries of the method were found to be 94.5,103.7% for mifepristone and 70.7,77.3% for monodemethyl-mifepristone. The method had a lower limit of quantification (LLOQ) of 5.0 ng/mL and a lower limit of detection (LOD) of 1.0 ng/mL for both mifepristone and monodemethyl-mifepristone. The intra- and inter-batch precision was less than 15% for all quality control samples at concentrations of 10, 100 and 1000 ng/mL. These results indicate that the method was efficient with a short run time (4.5 min) and acceptable accuracy, precision and sensitivity. The validated LC-MS/MS method was successfully used in a pharmacokinetic study in healthy female volunteers after oral administration of 25 mg mifepristone tablet. Copyright © 2008 John Wiley & Sons, Ltd. [source] Determination of picroside II in dog plasma by HPLC and its application in a pharmacokinetics studyBIOMEDICAL CHROMATOGRAPHY, Issue 4 2005Fu-Chuan Yang Abstract A sensitive and simple high-performance liquid chromatography method with UV detection was developed and validated for determining picroside II in dog plasma. Paeoni,orin was employed as internal standard and the sample pre-treatment procedure consists of deproteinization by addition of acetonitrile. Chromatographic separations were performed on a Shimadzu VP-ODS column (250 × 4.6 mm i.d., 5 µm). The mobile phase consisted of acetonitrile,0.1% acetic acid aqueous (v/v), 23:77, v/v, at a rate of 1 mL/min. Detection was carried out at a wavelength of 266 nm. Calibration standards ranged from 0.25 to 500 µg/mL in dog plasma and the mean correlation coef,cient of 0.9981 was found for the linear calibration curves (n = 6). The limit of quanti,cation (LOQ) was 0.25 µg/mL. Intra- and inter-assay RSD ranged from 0.70 to 7.5%. Accuracy (%bias) ranged from ,6.3 to 6.0%. This method was applied to the pharmacokinetic study of picroside II in dogs. The study demonstrated the plasma picroside II concentration,time curves were ,tted to the two-compartment open model and showed linear pharmacokinetics. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||