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High-performance Liquid Chromatographic Method (high-performance + liquid_chromatographic_method)
Kinds of High-performance Liquid Chromatographic Method Selected AbstractsHigh-performance liquid chromatographic method for identification and quantification of two isomeric coumarinolignoids,cleomiscosin A and cleomiscosin B,in extracts of Cleome viscosaBIOMEDICAL CHROMATOGRAPHY, Issue 11 2007Sunil K. Chattopadhyay Abstract A simple, accurate and reproducible reverse-phase HPLC method has been developed for identification and quantification of two isomeric coumarinolignoids, cleomiscosin A and B in different extracts of the seeds of Cleome viscosa using photodiode array detection at 326 nm. Cleomiscosin A and B were separated on a Waters symmetry C18 column (250 × 4.6 mm with 5.0 µm particle size) with an isocratic elution system composed of acetonitrile,methanol (1:2, v/v) and acetic acid,water (0.5:99.5, v/v) in the ratio of 40:60 (v/v). The calibration curves were linear (r2 > 0.997) in the concentration ranges of 20,100 µg/mL for both compounds. The limits of detection and quantification were 15 and 20 µg/mL for both cleomiscosin A and B. The intra- and inter-day precisions were 3.68 and 2.22% for cleomiscosin A and 4.22 and 5.06% for cleomiscosin B. The recoveries measured at two different concentration levels varied from 98.03 to 110.06%. The method was used to identify and quantify cleomiscosins A and B in different extracts of Cleome viscosa seeds. Copyright © 2007 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] Ketoconazole increases plasma concentrations of antimalarial mefloquine in healthy human volunteersJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 3 2005W. Ridtitid MD FCFPT Summary Background:, Antimalarial mefloquine has a structure related to quinine. The major metabolite of quinine is 3-hydroxyquinine formed by cytochrome P450 3A4 (CYP3A4). Ketoconazole, a potent inhibitor of CYP3A4, is known to markedly increase plasma concentrations of various co-administered drugs including quinine. Objective:, To assess the effect of ketoconazole on plasma concentrations of mefloquine in healthy Thai male volunteers. Methods:, In an open, randomized two-phase crossover study separated by a 1-month period, eight healthy Thai male volunteers received a single oral dose of 500 mg mefloquine alone or co-administration with 400 mg/day ketoconazole orally for 10 days. Serial blood samples were collected at specific time points for a 56-day period. Plasma mefloquine and mefloquine carboxylic metabolite concentrations during 56 days were measured by a modified and validated high-performance liquid chromatographic method with UV detection. Results:, Co-administration with ketoconazole markedly increased the mean values of mefloquine AUC0,t, t1/2, and Cmax when compared with mefloquine alone by 79% (P < 0·001), 39% (P < 0·05) and 64% (P < 0·001) respectively. The AUC0,t,, and Cmax of mefloquine carboxylic acid metabolite were decreased by 28% (P < 0·05) and 31% (P < 0·05), respectively when compared with mefloquine alone. Conclusions:, Co-administration with ketoconazole increased plasma mefloquine concentrations in healthy human volunteers. One of possible mechanisms of the increase in plasma mefloquine concentrations may be the result of the inhibition of CYP3A4 by ketoconazole. In case of mefloquine is co-administered with ketoconazole, drug,drug interactions should be recognized and the dose of mefloquine should be adjusted to maximize the therapeutic efficacy and to reduce the cost of therapy. [source] Separation and determination of small amounts of sulfur in technical thiophanate-methyl by reversed-phase high-performance liquid chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9-10 2003R. Nageswara Rao Abstract A simple and rapid reversed phase high-performance liquid chromatographic method for separation and determination of elemental sulfur in technical thiophanate-methyl using a reversed-phase C18 column and methanol-water-tetrahydrofuran (90 : 8 : 2 v/v/v) as eluent with UV detection at 254 nm has been developed and validated with respect to accuracy, precision, specificity, linearity range, and limits of detection and quantification. The method was found to be suitable not only for detection but also determination of elemental sulfur at levels of 5×10,9 g. [source] Determination of cyprodinil and fludioxonil in the fermentative process of must by high-performance liquid chromatography,diode array detectionJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2008Luis Vaquero-Fernández Abstract BACKGROUND: A quantitative, selective and sensitive high-performance liquid chromatographic method is described for the analysis of new fungicides cyprodinil, fludioxonil and their commercial formulation Switch in model solutions of must and wine, as well as samples during alcoholic fermentation. A study of the dissipation of residues was carried out. RESULTS: The proposed method is based on liquid,liquid extraction (LLE) followed by high-performance liquid chromatography and diode array detection. Dichloromethane was the most appropriate solvent for extracting cyprodinil and fludioxonil in samples. Quality parameters of the proposed method presented good recovery (ca. 97% for almost all compounds) and precision (between 4.8% and 5.4%), and limits of quantification were lower than maximum residue limits (MRLs) in grapes. CONCLUSIONS: There is no matrix effect in the analysis of cyprodinil and fludioxonil. The application of the fermentative process on cyprodinil and fludioxonil fungicides causes a decrease in the concentrations of these compounds. This decrease is slightly higher, the higher the initial concentration, without observing the appearance of any product in degradation. Fludioxonil shows a higher reduction when the compounds are presented together in Switch. Copyright © 2008 Society of Chemical Industry [source] A reversed-phase high-performance liquid chromatographic method for the determination of aloesin, aloeresin a and anthraquinone in Aloe feroxPHYTOCHEMICAL ANALYSIS, Issue 2 2008Michael Zahn Abstract A reversed-phase HPLC method for the quantification of aloesin, aloeresin a and anthraquinone (as barbaloin) in Aloe ferox Miller and aloe-related products has been developed and validated. The method utilized a C18 column with a water,methanol gradient and UV detection at 297 nm. The method validation included linearity, accuracy, precision, limit of detection, limit of quantitation, specificity and standard solution stability. The method showed good linearity (r > 0.99 for all components) and recovery (>85% for all components). The detection and quantitation limits for barbaloin were determined to be 0.02 and 0.1 ppm at signal-to-noise ratios of approximately 3:1 and 10:1, respectively. Copyright © 2007 John Wiley & Sons, Ltd. [source] Simultaneous quantification of eudesmanolides and thymol derivatives from tissues of Inula helenium and I. royleana by reversed-phase high-performance liquid ChromatographyPHYTOCHEMICAL ANALYSIS, Issue 3 2006Anna Stojakowska Abstract A simple and rapid isocratic reversed-phase high-performance liquid chromatographic method for the quantification of alantolactone/isoalantolactone and three thymol derivatives in roots and root cultures of Inula helenium and I. royleana has been developed. The method could be applied to screen raw materials in search for highly productive plants and in vitro cultures. Copyright © 2006 John Wiley & Sons, Ltd. [source] Stereospecific high-performance liquid chromatography of taxifolin, applications in pharmacokinetics, and determination in tu fu ling (Rhizoma smilacis glabrae) and apple (Malus × domestica)BIOMEDICAL CHROMATOGRAPHY, Issue 6 2009Karina R. Vega-Villa Abstract A stereospecific method of analysis of racemic taxifolin (+/,3,5,7,3,,4,-pentahydroxyflavanone) in biological fluids is necessary to study pharmacokinetics and disposition in fruit and herbs. A simple high-performance liquid chromatographic method was developed for the determination of all four taxifolin enantiomers. Separation was achieved on a Chiralcel® OJ-RH column with UV detection at 288 nm. The standard curves in serum were linear over a range of 0.5,100.0 µg/mL for each enantiomer. The mean extraction efficiency was >88.0%. Precision of the assay was <15% (CV), and was within 12% at the limit of quantitation (0.5 µg/mL). The bias of the assay was <15%, and was within 6% at the limit of quantitation. The assay was successfully applied to stereospecific disposition of taxifolin enantiomers in rats and to the quantification of taxifolin enantiomers in tu fu ling (Rhizoma smilacis glabrae) and apple (Malus × domestica). Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination and pharmacokinetic study of tussilagone in rat plasma by RP-HPLC methodBIOMEDICAL CHROMATOGRAPHY, Issue 11 2008Yu-Feng Liu Abstract A simple and rapid high-performance liquid chromatographic method was used to study the pharmacokinetics of tussilagone, one of the main bioactive constituents in the flower buds of Tussilago farfara L. of traditional Chinese medicines, in rat plasma. Plasma was deproteinized by ethyl acetate for sample clean-up. The drugs were separated on a Dikma DiamonsilÔ C18 column (4.6 × 250 mm, 5.0 µm), and detected by UV absorption at 220 nm. Methanol,water (75:25, v/v) was used as the mobile phase. It was applied to the pharmacokinetic study of tussilagone in rats after a dose of 5 mg/kg by intravenous administration and a dose of 200 mg/kg by intragastrical administration. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration,time curve by intravenous administration, while the plasma concentration,time curve of tussilagone conformed to a one-compartment model by intragastrical administration. The absolute bioavailability of tussilagone is about 1.31%. Copyright © 2008 John Wiley & Sons, Ltd. [source] Optimization and validation of RP-HPLC-UV method with solid-phase extraction for determination of buparvaquone in human and rabbit plasma: application to pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 5 2008Gantala Venkatesh Abstract A simple, sensitive and specific reversed-phase high-performance liquid chromatographic method with UV detection at 251 nm was developed for quantitation of buparvaquone (BPQ) in human and rabbit plasma. The method utilizes 250 µL of plasma and sample preparation involves protein precipitation followed by solid-phase extraction. The method was validated on a C18 column with mobile phase consisting of ammonium acetate buffer (0.02 m, pH 3.0) and acetonitrile in the ratio of 18:82 (v/v) at a flow rate of 1.1 mL/min. The calibration curves were linear (correlation coefficient ,0.998) in the selected range. The method is specific and sensitive with limit of quantitation of 50 ng/mL for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and BPQ was found to be stable. Partial validation studies were carried out using rabbit plasma and intra- and inter-day precision and accuracy were within 7%. This method is simple, reliable and can be routinely used for preclinical pharmacokinetic studies for BPQ. Copyright © 2007 John Wiley & Sons, Ltd. [source] HPLC determination of safflor yellow A and three active isoflavones from TCM Naodesheng in rat plasma and tissues and its application to pharmacokinetic studiesBIOMEDICAL CHROMATOGRAPHY, Issue 6 2007Zhiguo Yu Abstract A high-performance liquid chromatographic method was developed for the simultaneous determination and pharmacokinetic studies of safflor yellow A, puerarin, 3,-methoxyl-puerarin, and puerarinapioside in the plasma and tissues of rats that had been administered with the traditional Chinese medicine (TCM) preparation Naodesheng via the caudal vein. Samples taken from rats were subjected to protein precipitation with acetone. Separation of these four compounds was accomplished on a Kromisil C18 stationary phase using a mobile phase of acetonitrile,0.1% phosphoric acid,tetrahydrofuran (8:92:2, v/v/v) at a flow-rate of 1.0 mL/min. The detection wavelength was set at 250 nm. The calibration curves of the four components were linear in the given concentration ranges. The intra- and inter-day precisions in plasma and tissues were less than 15% and the extraction recoveries were higher than 60%. The lower limits of quantitation of four components were low enough to determine the four components. These four components all exhibited kinetics that fitted a two-compartment model in rats. The elimination half-life was 1.19 h for safflor yellow A, 2.69 h for puerarin, 2.94 h for 3,-methoxyl-puerarin, and 0.87 h for puerarinapioside, respectively. Following administration of a single injection of Naodesheng, the concentration (C) of the four components in the tissues showed Ckidney > Clung, Cliver > Cspleen, Cstomach, Cheart, approximately. The method is a reliable tool for performing studies of safflor yellow A and three puerarin isoflavones in different biological material. Copyright © 2007 John Wiley & Sons, Ltd. [source] A high-performance liquid chromatographic method for saikosaponin a quantification in rat plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 5 2007Yi-hong Tang Abstract A high-performance liquid chromatographic method with UV detection has been developed for the determination of saikosaponin a in rat plasma. Saikosaponin a and internal standard jujuboside A were isolated from plasma samples by solid-phase extraction. The chromatographic separation was achieved on a reversed-phase C18 column with the mobile phase of acetonitrile,water (35:65, v/v) at a flow rate of 1 mL/min and UV detection was set at 205 nm. The standard curve for saikosaponin a was linear over the concentration range 0.25,10 µg/mL and the limit of detection was 0.05 µg/mL. The absolute recovery was greater than 82%. The precision and accuracy ranged from 3.05 to 9.59% and 95.61 to 110.00%, respectively. The validated method was used to determine saikosaponin a in plasma samples in a pharmacokinetic study of saikosaponin a administered to Sprague,Dawley rats. Copyright © 2007 John Wiley & Sons, Ltd. [source] Simple determination of pirfenidone in rat plasma via high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 12 2006Yongsheng Wang Abstract A simple, rapid and reliable high-performance liquid chromatographic method was developed and validated for the determination of pirfenidone and its major metabolites in rat plasma. Plasma proteins were precipitated with perchloric acid (10%, v/v) and the supernatant after centrifugation was determined using high-performance liquid chromatography. The analysis was carried out on a Lichrospher C18 column (250 × 4.6 mm i.d., 5 µm). The mobile phase consisted of acetonitrile,water containing 0.2% acetic acid (23:77, v/v) at a flow-rate of 1 mL/min. The eluant was detected at 310 nm. The calibration curves were linear over a concentration range from 0.15 to 76.67 µg/mL. The accuracy (relative error) of the assay ranged from -2.6 to 7.9% and the precision (coefficient of variation) was less than 4.5%. The established method has been successfully applied to a pharmacokinetic study of pirfenidone following a single oral dose to rats. Copyright © 2006 John Wiley & Sons, Ltd. [source] A simple and sensitive HPLC-fluorescence method for quantification of MDMA and MDA in blood with 4-(4,5-diphenyl-1H -imidazol-2-yl)benzoyl chloride (DIB-Cl) as a labelBIOMEDICAL CHROMATOGRAPHY, Issue 12 2006Mamoru Tomita Abstract A sensitive high-performance liquid chromatographic method with fluorescence detection to determine 3,4-methylenedioxymethamphethamine (MDMA) and 3,4-methylenedioxyamphethamine (MDA) in human and rat whole blood or plasma samples was developed by using 4-(4,5-diphenyl-1H -imidazol-2-yl)benzoyl chloride (DIB-Cl) as a label. MDMA and MDA in a small amount of blood sample (ca 100 µL) were extracted by liquid,liquid extraction with ethyl acetate, and were derivatized with DIB-Cl under mild conditions (10 min at room temperature). A good separation of DIB-derivatives could be achieved within 45 min using a commercially available ODS column with an isocratic eluent of 10 mm citric acid,20 mm Na2HPO4 aqueous buffer (pH 4.0),CH3CN,CH3OH (50:45:5, v/v/v %). The calibration curves prepared with 1-methyl-3-phenylpropylamine (MPPA) as an internal standard showed good linearity (r = 0.999) with 0.36,0.83 ng/mL detection limit at a signal-to-noise ratio of 3. MDMA and MDA in rat whole blood could be monitored for 6 h after a single administration of MDMA (2.2 mg/kg, i.p.). The pharmacokinetic parameters for MDMA and MDA obtained by triplicate measurements were 426 ± 23 and 39 ± 6 ng/mL (Cmax), 20 ± 5 and 100 ± 10 min (Tmax), respectively. Copyright © 2006 John Wiley & Sons, Ltd. [source] Simultaneous determination of honokiol and magnolol in Magnolia officinalis by liquid chromatography with tandem mass spectrometric detectionBIOMEDICAL CHROMATOGRAPHY, Issue 10 2006Yu-Tse Wu Abstract An optimized high-performance liquid chromatographic method coupled with tandem mass spectrometric detection (LC-MS/MS) was developed for the simultaneous determination of honokiol and magnolol in Magnolia officinalis. Honokiol and magnolol were separated from the extracts using a reversed-phase C18 column with a mobile phase consisted of acetonitrile and water (75:25, v/v) at a flow-rate of 0.8 mL/min. Selected reaction monitoring (SRM) mode was used for all sample quantification by the precursor-ion/product ion pair m/z 265 , m/z 224 for honokiol and m/z 265 , m/z 247 for magnolol. Validation data showed that this method has good linearity (r2 > 0.995) over the concentration range of 0.0025,0.5 µg/mL for honokiol and magnolol, and both intra- and inter-day variability were acceptable within 15% at the lowest concentrations for this method. This proposed method provides excellent specificity, higher sensitivity and shorter run time than conventional methods and was applied successfully to determine the contents of honokiol and magnolol in M. officinalis. Copyright © 2006 John Wiley & Sons, Ltd. [source] Simple and rapid high-performance liquid chromatographic method for endogenous , -tocopherol determination in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 8 2006Katthaleeya Nirungsan Abstract A simple and rapid reversed-phase high-performance liquid chromatographic method was developed and validated for the determination of endogenous , -tocopherol in human plasma. Following addition of , -tocopheryl acetate as the internal standard, the plasma was deproteinized using acetonitrile and isopropanol mixture prior to HPLC analysis. Methanol was used as the mobile phase and the effluent was quantitated at 292 nm. By this developed method, the concentrations of , -tocopherol were linearly related to their responses in the range of 0.8,30 µg/mL. The relative standard deviations intra-day and inter-day for , -tocopherol in plasma were less than 10%. The percentage of bias was within ±4%, which confirmed the accuracy of the method. The method has been successfully applied for determining endogenous , -tocopherol in healthy Thai male volunteers. Copyright © 2005 John Wiley & Sons, Ltd. [source] Analysis of neuroactive amino acids from microdialysate samples by fluorescence detection using a modification of the 6-aminoquinolyl- N -hydroxysuccinimidyl carbamate methodBIOMEDICAL CHROMATOGRAPHY, Issue 10 2005M. Teresa Oreiro-García Abstract A sensitive and rapid reversed-phase high-performance liquid chromatographic method using pre-column derivatization with 6-aminoquinolyl- N -hydroxysuccinimidyl carbamate (AQC) and fluorescence detection is reported. By directly derivatizing microdialysate samples with AQC, an automatic and rapid simultaneous measurement of aspartate, serine, glutamate, glycine and histidine was developed. Excellent linearity (r2 , 0.998) was achieved for the standard mixture used for the validation experiments. Within-day and between-day precision was less than 6.2%, and the accuracy ranged from 95 to 105.2% in standards. This method is suitable for single run analysis of a high number of small volume microdialysate samples from rat hippocampus. Amino acids from microdialysate samples were quantified with RSD for reproducibility below 2%, and at approximately 0.1% for retention time. Copyright © 2005 John Wiley & Sons, Ltd. [source] A validated HPLC method with electrochemical detection for simultaneous assay of 5-aminosalicylic acid and its metabolite in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 5 2005Giancarlo Palumbo Abstract A high-performance liquid chromatographic method was developed, validated and applied to the simultaneous determination of 5-aminosalicylic acid (5-ASA) and its acetylated metabolite (acetyl-5-ASA) in human plasma. The method involves liquid,liquid extraction with methanol followed by isocratic reversed-phase chromatography on a Kromasil KR100 C18 column with electrochemical detection. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma samples. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modi,ers on retention of 5-ASA, acetyl 5-ASA and internal standard were investigated. Limits' of detection were 5 ng/mL for 5-ASA and 10 ng/mL for acetyl-5-ASA, respectively. The method can be used for supporting therapeutical drug monitoring and pharmacokinetic studies. Copyright © 2004 John Wiley & Sons, Ltd. [source] Rapid high-performance liquid chromatographic measurement of buspirone in human plasma after overdoseBIOMEDICAL CHROMATOGRAPHY, Issue 9 2004F. Péhourcq Abstract For toxicological purposes, a rapid reversed-phase high-performance liquid chromatographic method was developed for the determination of the anxiolytic drug, buspirone, in human plasma. A liquid,liquid procedure was used to extract this compound from plasma in the presence of an internal standard, quinupramine. The analysis was performed on a Spherisorb® S5 C8 analytical column with UV detection at 240 nm. No endogenous compounds were found to interfere. A linear response was observed over the concentration range 5,100 ng/mL. A good accuracy (bias ,7.9%) was achieved for all quality controls, with intra-day and inter-day variation coef,cients equal or less than 7.6%. The limit of quanti,cation was 5 ng/mL. Stability of buspirone in plasma stored at different temperatures was checked. This rapid method (run time <12 min) was used to manage an acute poisoning involving buspirone. Copyright © 2004 John Wiley & Sons, Ltd. [source] A simple and simultaneous determination of acyclovir and ganciclovir in human plasma by high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 8 2003Daisuke Teshima Abstract A simple high-performance liquid chromatographic method was developed for the simultaneous determination of the therapeutic levels of acyclovir and ganciclovir in human plasma. After precipitation of plasma proteins with 6% perchloric acid, acyclovir and ganciclovir were simultaneously determined by reversed-phase chromatography with spectophotometric detection at 254 nm. The peak heights for acyclovir and ganciclovir were linearly related to their concentrations ranging from 0.063 to 2.080 µg/mL. The recovery was 100.48,102.84% for acyclovir and 99.26,103.07% for ganciclovir. The intra- and inter-day relative standard deviation values were in the range 0.186,8.703% for acyclovir and 0.137,6.424% for ganciclovir. The detection limits for both compounds were 0.01 µg/mL determined as the signal-to-noise ratio of 3. The present method is applicable to therapeutic monitoring during antiviral medication. Copyright © 2003 John Wiley & Sons, Ltd. [source] Determination of paeonol in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies following oral administration of Moutan cortex decoctionBIOMEDICAL CHROMATOGRAPHY, Issue 8 2003Xinan Wu Abstract Quanti,cation of paeonol, the principal bioactive component of Moutan cortex, in rat plasma following oral administration of Moutan cortex decoction was achieved by using a simple and sensitive high-performance liquid chromatographic method. The calibration curves for paeonol were linear in both the low (25,200 ng/mL) and the high concentration range (200,4000 ng/mL) with r2 values of 0.9928 and 0.9993, respectively. The coef,cients of variation of intra- and inter-day assays were 14.36, 6.52, 1.76, 1.25, 5.36, 3.30 and 1.42% and 12.70, 1.19, 2.98, 1.91, 1.75, 1.78 and 0.96% at concentrations of 25, 50, 100, 200, 500, 1000 and 2000 ng/mL, respectively. The recoveries of paeonol from rat plasma were found to be 101.9, 104.5, 105.4 and 101.2% for concentrations of 50, 500, 1000 and 2000 ng/mL, respectively. The paeonol plasma concentrations were ,tted to two-compartment model with ,rst order absorption. The mean terminal half-lives (t1/2) of paeonol was 80.9 min. Copyright © 2003 John Wiley & Sons, Ltd. [source] Simultaneous determination of four antiepileptic drugs in serum by high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 1 2002H. Levert A high-performance liquid chromatographic method has been developed for the simultaneous determination of oxcarbazepine, 10-hydroxycarbamazepine, epoxycarbamazepine, carbamazepine, phenobarbital and phenytoin. After protein precipitation by acetonitrile, the supernatant was analysed on a C18 reversed-phase HPLC column. Antiepileptic drugs and oxazepam (internal standard) were detected by ultraviolet absorbance at 240,nm. Linearity was established for the whole concentration range for each compound. Quantitation limits of oxcarbazepine, 10-hydroxycarbamazepine, epoxycarbamazepine, carbamazepine, phenobarbital and phenytoin were 0.58, 3.5, 2.35, 0.66, 1.02 and 3.13,µg/mL, respectively, and mean recoveries added to serum were 105.15, 84.76, 94,45, 96.52, 98.62 and 95.08%, respectively. This method has been used for the simultaneous determination of steady-state serum concentration of antiepileptic drugs in patients treated by one or more anticonvulsive treatment. Copyright © 2001 John Wiley & Sons, Ltd. [source] Chiral Separation of Calcium (,)-2(S)-2-Benzyl-4-oxo-4-(cis -hexahydro-2-isoindolinyl)butyrate Enantiomers by High-performance Liquid Chromatography,CHINESE JOURNAL OF CHEMISTRY, Issue 1 2009Zhefeng ZHANG Abstract A chiral high-performance liquid chromatographic method was developed for the enantioseparation of a new insulinotropic drug of the glinide class with rapid onset. The chiral separation was performed on a Sumichiral OA-3300 column (250 mm×4.6 mm, 5 µm) with methanol containing 0.05 mol/L ammonium acetate as the optimized mobile phase at detection wavelengh 210 nm. Baseline separation of the two enantiomers was obtained in 22 min with a resolution of 3.01. Calibration graphs were constructed in a range of 0.028,5.6 µg·mL,1 for S - and 0.03,6.0 µg·mL,1 for R -(,)-enantiomer, respectively. The linear correlation equations are: y=1.32×103x,2.54 (r=0.9997) for S -enantiomer and y=1.15×103x,1.78 (r=0.9998) for R -enantiomer, respectively. The limits of detection obtained by S/N=3 were 0.15 ng for S - and 0.10 ng for R -enantiomer, respectively. RSD of the method was below 1.0% (n=5). [source] | ||||||||||