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High-performance Liquid Chromatographic (high-performance + liquid_chromatographic)
Terms modified by High-performance Liquid Chromatographic Selected AbstractsHigh-performance liquid chromatographic assay for the active saponins from Panax notoginseng in rat tissuesBIOMEDICAL CHROMATOGRAPHY, Issue 4 2006Lie Li Abstract A reversed-phase liquid chromatographic method was used to determine the ginsenosides Rg1, Rb1 and Rd of Panax notoginseng in rat tissues (kidney, liver, heart, spleen and lung) after the administration of total saponins of P. notoginseng. The tissue samples were treated with solid-phase extraction prior to HPLC. The calibration curves for the three saponins were linear in the given concentration ranges. The intra-day and inter-day assay coefficients in tissues were between 76 and 120% respectively. The recoveries of all the tissues were higher than 70%. This method was applied to evaluate the distribution of the three major saponins of P. notoginseng in rat tissues. Copyright © 2005 John Wiley & Sons, Ltd. [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] 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] 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] 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] 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] Kinetic distribution of paeoniflorin in cortex of normal and cerebral ischemia-reperfusion rats after intravenous administration of Paeoniae Radix extractBIOMEDICAL CHROMATOGRAPHY, Issue 12 2006Chunai Cao Abstract The time course of paeoniflorin in the cortex of normal and cerebral ischemia,reperfusion rats, following intravenous administration of Paeoniae Radix extract at a dose of 60 mg/kg of paeoniflorin, was determined using high-performance liquid chromatographic (HPLC) assay. The results showed that paeoniflorin could penetrate through the blood,brain barrier to reach the cortex, and that the injuries of ischemia,reperfusion could play an important role in pharmacokinetic process of paeoniflorin in the cortex after intravenous administration of Paeoniae Radix extract. The cortex concentrations of paeoniflorin in cerebral ischemia,reperfusion rats were lower 5 min after dosing and declined more slowly than that in normal control. Copyright © 2006 John Wiley & Sons, Ltd. [source] Determination and pharmacokinetic study of bergenin in rat plasma by RP-HPLC methodBIOMEDICAL CHROMATOGRAPHY, Issue 10 2006Yan-Bin Shi Abstract A validated reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the determination of bergenin in rat plasma. Bergenin in rat plasma was extracted with methanol, which also acted as a deproteinization agent. Chromatographic separation of bergenin was performed on a C18 column, with a mobile phase of methanol,water (22:78, v/v) at a flow-rate of 0.8 mL/min and an operating temperature of 40°C, and UV detection was set at 220 nm. The calibration curve was linear over the range 0.25,50 µg/mL (r = 0.9990) in rat plasma. The limit of quantification was 0.25 µg/mL using a plasma sample of 100 µL. The extraction recoveries were 83.40 ± 6.02, 81.49 ± 2.40 and 72.51 ± 2.64% at concentrations of 0.5, 5 and 50 µg/mL, respectively. The intra-day and inter-day precision and accuracy were validated by relative standard deviation (RSD%) and relative error (RE%), which were in the ranges 3.74,9.91 and ,1.6,8.0%. After intravenous administration to rats at the dose of 11.25 mg/kg, the plasma concentration,time curve of bergenin was best conformed to a two-compartment open model. The main pharmacokinetic parameters indicated that bergenin exhibited a wide distribution and moderate elimination velocity in rat. Copyright © 2006 John Wiley & Sons, Ltd. [source] High-performance liquid chromatographic method for simple and rapid determination of linezolid in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 8 2006Lauren M. Boak Abstract A simple high-performance liquid chromatographic (HPLC) method was developed and validated for rapid quantification of linezolid in human plasma. Protein precipitation using a mixture of 5% trichloroacetic acid and methanol (3:1, v/v) provided a straightforward method of sample preparation and the internal standard eperezolid was employed. A concentration range from 0.20 to 40.0 mg/L was utilized to construct calibration curves, and analysis of low- (0.40 mg/L), medium- (7.50 mg/L) and high-quality (25.0 mg/L) control samples revealed excellent reproducibility (,3.88%) and accuracy (,4.20%). The recovery of both linezolid and eperezolid was approximately 100%. No interference was observed at the retention times of linezolid and eperezolid from blank plasma or eight commonly used antibiotics. Tests confirmed the stability of linezolid in plasma during three freeze,thaw cycles, on the bench during 24 h and during long-term storage of frozen plasma for up to 12 weeks; in extracts it was stable in the HPLC autosampler over 12 h. Overall, this assay offers a highly simplistic approach to quantifying linezolid in plasma, and would be well suited to clinical pharmacokinetic, pharmacodynamic and toxicodynamic analyses. Copyright © 2005 John Wiley & Sons, Ltd. [source] Simultaneous determination of amantadine and rimantadine by HPLC in rat plasma with pre-column derivatization and fluorescence detection for pharmacokinetic studiesBIOMEDICAL CHROMATOGRAPHY, Issue 9 2005Yasuhiko Higashi Abstract We investigated simultaneous high-performance liquid chromatographic (HPLC) determination of amantadine hydrochloride (AMA) and rimantadine hydrochloride (RIM) levels in rat plasma after fluorescent derivatization with o -phthalaldehyde and 2-mercaptoethanol. Afterwards, the method was applied to determine their pharmacokinetics. The retention times of AMA and RIM derivatives were 12.6 and 22.2 min and the lower limits of detection were 0.025 and 0.016 µg[sol ]mL, respectively. The coefficients of variation for intra- and inter-day assay of AMA and RIM were less than 5.1 and 7.6%, respectively. After i.v. administration of AMA or RIM to rats, the total body clearance and distribution volume at the steady-state of RIM were higher than those of AMA. Bioavailability of AMA and RIM was 34.9 and 37.2%, respectively. When AMA and RIM were p.o. co-administered, the area under the plasma concentration,time curve of RIM was significantly lower than that after RIM alone. On the other hand, pharmacokinetic parameters of AMA did not significantly change. These results indicate that our HPLC assay is simple, rapid, sensitive and reproducible for simultaneously determining AMA and RIM concentrations in rat plasma and is applicable to their pharmacokinetic studies. Also, co-administration of AMA and RIM may result in the lack of pharmacological effects of RIM. Copyright © 2005 John Wiley & Sons, Ltd. [source] A chromatographic method for baicalin quanti,cation in rat thalamusBIOMEDICAL CHROMATOGRAPHY, Issue 7 2005Lujun Zhang Abstract A rapid reversed-phase high-performance liquid chromatographic (rp-HPLC) assay for the determination of baicalin in rat thalamus was developed. This was carried out on a Hypersil ,C18 column using 4-nitro-benzoic acid as the internal standard with a mobile phase of methanol,water,H3PO4 (45:55:0.2, v/v/v). Detection was by UV at 277 nm. The calibration curve for baicalin was linear (r = 0.9992) over the concentration range of 0.05,4.0 µg/mL and the limit of detection was 10 ng/mL. The coef,cients of variation of intra- and inter-day assays were 2.64, 5.19 and 3.19% and 3.46, 6.21 and 5.58% at concentrations of 0.5, 1.0 and 3.0 µg/mL, respectively. The recoveries of baicalin from rat thalamus were 85.4 ± 5.62, 90.7 ± 2.43 and 89.1 ± 4.75% at concentrations of 0.5, 1.0 and 3.0 µg/mL, respectively. The method was applied to determine the time course of baicalin in rat thalamus, following a single dosage of intravenous administration of Scutellariae radix extract at 90 mg/kg of baicalin to male Wistar rats. Copyright © 2005 John Wiley & Sons, Ltd. [source] Determination of the uronic acid composition of seaweed dietary ,bre by HPLCBIOMEDICAL CHROMATOGRAPHY, Issue 2 2004D. I. Sánchez-Machado Abstract A high-performance liquid chromatographic (HPLC) method is described for determination of the ratio of , - d -mannuronic acid to , - l -guluronic acid (M/G ratio) in dietary ,bre of edible seaweeds. Total dietary ,bre (TDF) content was determined gravimetrically. The TDF fraction was hydrolysed with 12 m and 1 m H2SO4, then neutralized with AG 4 × 4 resin. The uronic acids were separated in a Tracer Extrasil SAX 5 µm column (25 cm × 4 mm) at 35°C, with 2 mm KH2PO4 containing 5% methanol as mobile phase at a ,ow rate of 1.5 mL/min. The detection wavelength was UV 210 nm. The chromatographic identi,cations of , - d -mannuronic acid and , - l -guluronic acid were con,rmed by liquid chromatography,mass spectrometry (LC-MS). The method precision was 1.4% for , - d -mannuronic acid and 3.5% for , - l -guluronic acid. The method was used to determine M/G ratio in canned seaweeds (Saccorhiza polyschides and Himanthalia elongata) and in dried seaweeds (H. elongata, Laminaria ochroleuca, Undaria pinnati,da, Palmaria sp. and Porphyra sp.). Copyright © 2003 John Wiley & Sons, Ltd. [source] Determination of the ,avone tricin in human plasma by high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 7 2003Hong Cai Abstract Tricin is a ,avone constituent of brown rice and rice bran, which interferes potently with the survival of human-derived breast and colon cancer cells in vitro. A speci,c and simple high-performance liquid chromatographic (HPLC) method was developed for the determination of tricin in human plasma with UV,visible detection. HPLC separation on Hypersil-BDS C18 (4.6 × 250 mm) was carried out with an isocratic mobile phase of 52% methanol in 0.1 m ammonium acetate, pH 5.10, containing 0.27 mm disodium ethylenediamine tetraacetic acid and detection at 355 nm. The retention times of tricin and quercetin (internal standard) were 14.2 and 7.8 min, respectively. The assay was linear in the range 1,100 µg/mL (r2 , 0.995). Tricin in plasma was ef,ciently extracted with 0.1 m acetic acid in acetone, and the recoveries were in the range 92.6,102.8% (n = 6) with relative standard deviation below 10% for three concentrations of tricin, 5, 10 and 100 µg/mL. The lower limit of quantitation (relative standard deviation <20%) was 1 µg/mL. Copyright © 2003 John Wiley & Sons, Ltd. [source] Comparative pharmacokinetics of single doses of doxylamine succinate following intranasal, oral and intravenous administration in ratsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 6 2002Andries Pelser Abstract The intranasal route of administration provides a potential useful way of administering a range of systemic drugs. In order to assess the feasibility of this approach for the treatment of nausea and vomiting, doxylamine succinate was studied in rats for the pharmacokinetics (AUC, Cmax, tmax) following intranasal, oral and intravenous administrations. Subjects (six male Sprague,Dawley rats per time interval for each route of administration) received 2-mg doses of doxylamine succinate orally and I-mg doses intranasally and intravenously, respectively. The various formulations were formulated in isotonic saline (0.9% w/v) at 25±1°C. Doxylamine succinate concentrations in plasma were determined with a high-performance liquid chromatographic assay and a liquid,liquid extraction procedure. Intranasal and oral bioavailabilities were determined from AUC values relative to those after intravenous dosing. Intranasal bioavailability was greater than that of oral doxylamine succinate (70.8 vs 24.7%). The intranasal and oral routes of administration differed significantly from the intravenous route of administration. Peak plasma concentration (Cmax) was 887.6 ng/ml (S.D. 74.4), 281.4 ng/ml (S.D. 24.6) and 1296.4 ng/ml (S.D. 388.9) for the intranasal, oral and intravenous routes, respectively. The time to achieve Cmax for the intranasal route (tmax=0.5 h) was faster than for the oral route (tmax=1.5 h), but no statistically significant differences between the Cmax values were found using 95% confidence intervals. The results of this study show that doxylamine succinate is rapidly and effectively absorbed from the nasal mucosa. Copyright © 2002 John Wiley & Sons, Ltd. [source] | |||||||||||||