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1.
Fluorodensitometric evaluation of gentamicin from plasma and urine by high-performance thin-layer chromatography 总被引:1,自引:0,他引:1
Chhanda P Bhogte V.B Patravale Padma V Devarajan 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,694(2):1246
High-performance thin-layer chromatographic (HPTLC) analysis of gentamicin by in situ fluorodensitometric evaluation of its 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) derivative is presented. The aminoglycoside components separated on silica gel plates using chloroform–methanol–20% ammonium hydroxide (2.4:2.2:1.5, v/v/v) as the mobile phase were reacted with NB-Cl to yield highly fluorescent derivatives. The calibration curves of gentamicin in water, plasma and urine were linear in the range 40–200 ng. The mean values of intercept, slope and correlation coefficient were 16.82±0.473, 6.83±0.015 and 0.9968±0.0017 for standard curves in water, 17.35±0.375, 6.85±0.018 and 0.9941±0.0012 for standard curves in plasma and 14.35±0.286, 6.86±0.002 and 0.9933+0.0011 for standard curves in urine respectively. The analytical technique was validated for within-day and day-to-day variation. The results indicate that HPTLC, coupled with in situ fluorodensitometry, is a reliable and valuable technique for quantitative analysis of the bulk drug gentamicin and gentamicin from urine and plasma. 相似文献
2.
Peter de Bruijn Diederik F. S. Kehrer Jaap Verweij Alex Sparreboom 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,753(2):395-400
A high-performance liquid chromatographic assay with UV detection has been developed for the determination of ketoconazole in human plasma. Quantitative extraction was achieved by a single solvent extraction involving a mixture of acetonitrile–n-butyl chloride (1:4, v/v). Ketoconazole and the internal standard (clotrimazole) were separated on a column packed with Inertsil ODS-80A material and a mobile phase composed of water–acetonitrile–tetrahydrofuran–ammonium hydroxide–triethylamine (45:50.2:2.5:0.1:0.1, v/v). The column effluent was monitored at a wavelength of 206 nm with a detector range set at 0.5. The calibration graph was linear in the range of 20–2000 ng/ml, with a lower limit of quantitation of 20.0 ng/ml. The extraction recoveries for ketoconazole and clotrimazole in human plasma were 93±9.7% and 83±10.0%, respectively. The developed method has been successfully applied to a clinical study to examine the pharmacokinetics of ketoconazole in a cancer patient. 相似文献
3.
Sharif M. Mansor V. Navaratnam Norizah Yahaya N.K. Nair W.H. Wernsdorfer P.H. Degen 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,682(2):321
A rapid and selective high-performance liquid chromatographic assay for determination of a new antimalarial drug (benflumetol, BFL) is described. After extraction with hexane-diethyl ether (70:30, v/v) from plasma, BFL was analysed using a C18 Partisil 10 ODS-3 reversed-phase stainless steel column and a mobile phase of acetonitrile-0.1 M ammonium acetate (90:10, v/v) adjusted to pH 4.9 with ultraviolet detection at 335 nm. The mean recovery of BFL over a concentration range of 50–400 ng/ml was 96.8±5.2%. The within-day and day-to-day coefficients of variation were 1.8–4.0 and 1.8–4.2%, respectively. The minimum detectable concentration in plasma for BFL was 5 ng/ml with a C.V. of less than 10%. This method was found to be suitable for clinical pharmacokinetic studies. 相似文献
4.
David W. Boulton John S. Markowitz C. Lindsay DeVane 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,759(2):319-323
Olanzapine is a commonly used atypical antipsychotic medication for which therapeutic drug monitoring has been proposed as clinically useful. A sensitive method was developed for the determination of olanzapine concentrations in plasma and urine by high-performance liquid chromatography with low-wavelength ultraviolet absorption detection (214 nm). A single-step liquid–liquid extraction procedure using heptane-iso-amyl alcohol (97.5:2.5 v/v) was employed to recover olanzapine and the internal standard (a 2-ethylated olanzapine derivative) from the biological matrices which were adjusted to pH 10 with 1 M carbonate buffer. Detector response was linear from 1–5000 ng (r2>0.98). The limit of detection of the assay (signal:noise=3:1) and the lower limit of quantitation were 0.75 ng and 1 ng/ml of olanzapine, respectively. Interday variation for olanzapine 50 ng/ml in plasma and urine was 5.2% and 7.1% (n=5), respectively, and 9.5 and 12.3% at 1 ng/ml (n=5). Intraday variation for olanzapine 50 ng/ml in plasma and urine was 8.1% and 9.6% (n=15), respectively, and 14.2 and 17.1% at 1 ng/ml (n=15). The recoveries of olanzapine (50 ng/ml) and the internal standard were 83±6 and 92±6% in plasma, respectively, and 79±7 and 89±7% in urine, respectively. Accuracy was 96% and 93% at 50 and 1 ng/ml, respectively. The applicability of the assay was demonstrated by determining plasma concentrations of olanzapine in a healthy male volunteer for 48 h following a single oral dose of 5 mg olanzapine. This method is suitable for studying olanzapine disposition in single or multiple-dose pharmacokinetic studies. 相似文献
5.
Eun-Hee Joo Woo-Ik Chang Injoon Oh Sang-Chul Shin Han-Kwang Na Yong-Bok Lee 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,723(1-2)
A rapid, selective and very sensitive ion-pairing reversed-phase HPLC method was developed for the simultaneous determination of trimebutine (TMB) and its major metabolite, N-monodesmethyltrimebutine (NDTMB), in rat and human plasma. Heptanesulfonate was employed as the ion-pairing agent and verapamil was used as the internal standard. The method involved the extraction with a n-hexane–isopropylalcohol (IPA) mixture (99:1, v/v) followed by back-extraction into 0.1 M hydrochloric acid and evaporation to dryness. HPLC analysis was carried out using a 4-μm particle size, C18-bonded silica column and water–sodium acetate–heptanesulfonate–acetonitrile as the mobile phase and UV detection at 267 nm. The chromatograms showed good resolution and sensitivity and no interference of plasma. The mean recoveries for human plasma were 95.4±3.1% for TMB and 89.4±4.1% for NDTMB. The detection limits of TMB and its metabolite, NDTMB, in human plasma were 1 and 5 ng/ml, respectively. The calibration curves were linear over the concentration range 10–5000 ng/ml for TMB and 25–25000 ng/ml for NDTMB with correlation coefficients greater than 0.999 and with within-day or between-day coefficients of variation not exceeding 9.4%. This assay procedure was applied to the study of metabolite pharmacokinetics of TMB in rat and the human. 相似文献
6.
Stephen C. Kasper Edward L. Mattiuz Steven P. Swanson Jenting Andre Chiu Jason T. Johnson Carlos O. Garner 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,726(1-2)
A reversed-phase high-performance liquid chromatographic–electrochemical assay was developed and validated for the quantification of olanzapine in human breast milk. The assay involved a solid-phase extraction (SPE) of olanzapine and its internal standard on a Bond Elut Certify LRC mixed-mode cartridge. After conditioning of the SPE cartridge, human milk (1 ml) was passed through the cartridge. The cartridge was washed with five separate washing steps to remove endogenous compounds, and the analytes were eluted with ethyl acetate–ammonium hydroxide (98:2, v/v) solution. The eluate was evaporated to dryness (gentle stream of nitrogen at 40°C), and the residue was dissolved in mobile phase. The extract was injected onto a YMC basic column (150 mm×4.6 mm I.D., 5 μm particle size) at a flow-rate of 1 ml/min. A mixture of 75 mM phosphate buffer, pH 7.0–acetonitrile–methanol (48:26:26, v/v/v) was used as the mobile phase. Standard curves with a lower limit of quantitation of 0.25 ng/ml of olanzapine were linear (r2≥0.9992) over a range of 0.25–100 ng/ml. Based on the analysis of quality control (QC) samples, the average inter-day accuracy (RE) was 99.0% with an average precision (CV) of 6.64% over the entire range. The stability of olanzapine in human milk was established after three freeze–thaw–heat cycles and storage at −70°C for 10 months. The validated method was used to measure olanzapine concentrations in human milk during a clinical trial. 相似文献
7.
Tung-Hu Tsai Yen-Fei Chen I-Fei Chen Chieh-Fu Chen 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,729(1-2)
To monitor the levels of caffeic acid in rat blood, an on-line microdialysis system coupled with liquid chromatography was developed. The microdialysis probe was inserted into the jugular vein/right atrium of male Sprague-Dawley rats. Caffeic acid (100 mg/kg, i.v.) was then administered via the femoral vein. Dialysates were automatically injected onto a liquid chromatographic system via an on-line injector. Samples were eluted with a mobile phase containing methanol–100 mM monosodium phosphoric acid (35:65, v/v, pH 2.5). The UV detector wavelength was set at 320 nm. The detection limit of caffeic acid was 20 ng/ml. The in vivo recoveries of the microdialysis probe for caffeic acid at 0.5 and 1 μg/ml were 48.34±2.68 and 47.64±3.43%, respectively (n=6). Intra- and inter-assay accuracy and precision of the analyses were ≤10% in the range of 0.05 to 10 μg/ml. Pharmacokinetics analysis of results obtained using such a microdialysis–chromatographic method indicated that unbound caffeic acid in the rat fitted best to a biexponential decay model. 相似文献
8.
Iman Barilero Daniel Gandia Jean-Pierre Armand Anne Mathieu-Bou Micheline R Alain Gouyette Guy G. Chabot 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1992,575(2)
CPT-11 {I; 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin} is a new anticancer agent currently under clinical development. A sensitive high-performance liquid chromatographic assay suitable for the simultaneous determination of I and its active metabolite SN-38 (II) in human plasma, and their preliminary clinical pharmacokinetics, are described. Plasma samples were processed using a solid-phase (C18) extraction step allowing mean recoveries of I, II and the internal standard camptothecin (III) of 84, 99 and 72%, respectively. The extracts were chromatographed on a C18 reversed-phase column with a mobile phase composed of acetonitrile, phosphate buffer and heptanesulphonic acid, with fluorescence detection. The calibration graphs were linear over a wide range of concentrations (1 ng/ml–10 μg/ml), and the lower limit of determination was 1 ng/ml for both I and II. The method showed good precision: the within-day relative standard deviation (R.S.D.) (5–1000 ng/ml) was 13.0% (range 4.9–19.4%) for I and 12.8% (6.7–19.1%) for II; the between-day R.S.D. (5–10 000 ng/ml was 7.9% (5.4–17.5%) for I and 9.7% (3.5–15.1%) for II. Using this assay, plasma pharmacokinetics of both I and II were simultaneously determined in three patients receiving 100 mg/m2 I as a 30-min intravenous infusion. The mean peak plasma concentration of I at the end of the intravenous infusion was 2400 ± 285 ng/ml (mean ± standard error of the mean). Plasma decay was triphasic with half-lives α, β and γ of 5.4 ± 1.8 min, 2.5 ± 0.5 h and 20.2 ± 4.6 h, respectively. The volume of distribution at steady state was 105 ± 15 l/m2, and the total body clearance was 12.5 ± 1.9 l/h · m2. The maximum concentrations of the active metabolite II reached 36 ± 11 ng/ml. 相似文献
9.
Masahiko Obayashi Takayoshi Kosugi Jun-ichi Yamazaki Yoshiaki Matsumoto Masamichi Fukuoka Mitsuo Matsumoto 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,726(1-2)
An optimized method for the determination of flecainide in serum is presented. Extraction using a solid-phase C18 column and chromatography on a stabilized fluorocarbon-bonded silica gel column effectively separate flecainide from an internal standard (a positional isomer of flecainide). The HPLC apparatus and conditions were as follows: analytical column, Fluofix 120N; sample solvent, 20 μl; column temperature, 40°C; detector, Shimadzu RF-5000 fluorescence spectrophotometer (excitation wavelength=300 nm, emission wavelength=370 nm); mobile phase, 0.06% phosphoric acid containing 0.1% tetra-n-butyl ammonium bromide–acetonitrile (75:25, v/v); flow-rate, 1.0 ml/min. The standard curves for flecainide were linear in the concentration range examined (10–2000 ng/ml). The regression equation was y=0.08+0.0078x (r=0.9998). The minimum detectable amount of flecainide was approximately 5 ng/ml. In the within-day study, the precision coefficients of variation were 2.66, 2.18, 2.54, 2.72, 2.88, 2.24, and 3.29% for the 10, 50, 100, 200, 500, 1000, and 1500 ng/ml standards, respectively. The absolute recovery rates of flecainide at each concentrations were 94–100%. The method described provides analytical sensitivity, specificity and reproducibility suitable for both biomedical research and therapeutic drug monitoring. 相似文献
10.
S. Ramanathan N.K. Nair S.M. Mansor V. Navaratnam 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,615(2)
A rapid and selective high-performance liquid chromatographic assay for simultaneous quantitative determination of a new antifilarial drug (UMF-058, I) and mebendazole (MBZ) is described. After a simple extraction from whole blood, both compounds were analysed using a C18 Nova Pak reversed-phase column and a mobile phase of methanol—0.05 M ammonium dihydrogenphosphate (50:50, v/v) adjusted to pH 4.0, with ultraviolet detection at 291 nm. The average recoveries of I and MBZ over a concentration range of 25–250 ng/ml were 92.0 ± 7.7 and 84.4 ± 4.4%, respectively. The minimum detectable concentrations in whole blood for I and MBZ were 7 and 6 ng/ml, respectively. This method was found to be suitable for pharmacokinetic studies. 相似文献
11.
J. MacCallum J. Cummings J.M. Dixon W.R. Miller 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,678(2):317-323
Tamoxifen (TAM) is a triphenylethylene anti-oestrogen, commonly used in the treatment of breast cancer. Patients receiving tamoxifen therapy may experience both de novo and acquired resistance. As one of the mechanisms for this may be extensive peripheral bio-transformation of tamoxifen, there has been considerable interest in the pharmacokinetics and metabolism of tamoxifen. A reversed-phase high-performance liquid chromatography separation has been developed to determine the levels of tamoxifen and its major metabolites in human plasma. The method is highly sensitive (2 ng/ml) and selective for tamoxifen, cis-tamoxifen (CIS), 4-hydroxytamoxifen (4-OH) and desmethyltamoxifen (DMT). A μBondapak C18 10 μm column (30 cm × 3.9 mm I.D.) was used, with a mobile phase of methanol-1% triethylamine at pH 8 (89:11, v/v). Sample preparation was carried out using a C2 (500 mg sorbent, 3 ml reservoirs) solid phase extraction method, and extraction efficiencies were approximately 60% for TAM and its metabolites. Accuracy and precision, as determined by spiking plasma samples with a mixture of tamoxifen and its metabolites, ranged from 85–110% (± 5–10%) at 1 μg/ml, 101–118% (± 8–20%) at 0.1 μg/ml and 111–168% (± 43–63%) at 0.01 μg/ml. Results from 59 patients show mean values of 54 ng/ml for 4-OH; 190 ng/ml for DMT; 93 ng/ml for TAM and 30 ng/ml for CIS (detected in three patients only). This methodology can be applied routinely to the determination of TAM and its metabolites in plasma from patients undergoing therapy. 相似文献
12.
Michael Lovdahl Jeffery Steury Henry Russlie Daniel M. Canafax 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,617(2)
An isocratic high-performance liquid chromatographic method has been developed to determine ciprofloxacin levels in chinchilla plasma and middle ear fluid. Ciprofloxacin and the internal standard, difloxacin, were separated on a Keystone ODS column (100 × 2.1 mm I.D., 5 μm Hypersil) using a mobile phase of 30 mM phosphate buffer (pH 3), 20 mM triethylamine, 20 mM sodium dodecyl sulphate—acetonitrile (60:40, v/v). The retention times were 3.0 min for ciprofloxacin and 5.2 min for difloxacin. This fast, efficient protein precipitation procedure together with fluorescence detection allows a quantification limit of 25 ng/ml with a 50 μl sample size. The detection limit is 5 ng/ml with a signal-to-noise ratio of 5:1. Recoveries (mean ± S.D., n = 5) at 100 ng/ml in plasma and middle ear fluid were 89.4 ± 1.2% and 91.4 ± 1.6%, respectively. The method was evaluated with biological samples taken from chinchillas with middle ear infections after administering ciprofloxacin. 相似文献
13.
R. S. Addison M. E. Franklin W. D. Hooper 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1998,716(1-2)
A sensitive, robust gas chromatographic–mass spectrometric assay suitable for use in pharmacokinetic or bioequivalence studies is presented for the selective serotonin reuptake inhibitor, fluoxetine, and its major metabolite, norfluoxetine (N-desmethylfluoxetine). This method employs solid-phase extraction followed by acetylation with trifluoroacetic anhydride and analysis of the derivatives using selected ion monitoring. The lower limit of quantification was 1.0 ng/ml, and the assay was linear for both analytes from 1 to 100 ng/ml. Mean recoveries following solid-phase extraction at concentrations of 5.0, 20 and 100 ng/ml were 91% (fluoxetine) and 87% (norfluoxetine). Assay precision (as mean RSD) and accuracy (as mean relative error) for both analytes were tested at the same three nominal concentrations and were found to be within 10% in all cases. Analysis of fluoxetine concentrations in plasma samples from 18 volunteers following administration of a single 40 mg dose of fluoxetine provided the following pharmacokinetic data (mean±SD): Cmax, 32.73±9.21 ng/ml; AUC0–∞, 1627±1372 ng/ml h; Tmax, 3.08 h (median); ke, 0.022±0.007 h−1; elimination half-life, 37.69±21.70 h. 相似文献
14.
Mitsuhiro Ishida Kayoko Kobayashi Norio Awata Fumio Sakamoto 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,727(1-2)
A simple and reproducible method for the analysis of ampicillin in human serum was developed. Serum samples were extracted using solid-phase extraction disk cartridges containing a sorbent of styrene divinyl/benzene. Extracts were separated by reversed-phase C18 high-performance liquid chromatography with UV detection at 220 nm. The mobile phase consisted of acetonitrile–10 mM NaH2PO4 (6.5:93.5, v/v). Using this extraction procedure, recovery from serum was 98.4±5.6%. The quantitation limit was 0.19 μg/ml using 0.5 ml of serum. The calibration curves from 0.19 to 9.41 μg/ml were linear with correlation coefficients of 0.999. This method is suitable for therapeutic drug monitoring of ampicillin (ABPC) after oral administration of lenampicillin hydrochloride. 相似文献
15.
Hyun Mee Lee Sung Jin Choi Chang Kyun Jeong Yong Seok Kim Kang Choon Lee Hye Suk Lee 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,727(1-2)
For the determination of cisapride from serum samples, an automated microbore high-performance liquid chromatographic method with column switching has been developed. After serum samples (100 μl) were directly injected onto a Capcell Pak MF Ph-1 pre-column (10×4 mm I.D.), the deproteinization and concentration were carried out by acetonitrile–phosphate buffer (20 mM, pH 7.0) (2:8, v/v) at valve position A. At 2.6 min, the valve was switched to position B and the concentrated analytes were transferred from MF Ph-1 pre-column to a C18 intermediate column (35×2 mm I.D.) using washing solvent. By valve switching to position A at 4.3 min, the analytes were separated on a Capcell Pak C18 UG 120 column (250×1.5 mm I.D.) with acetonitrile–phosphate buffer (20 mM, pH 7.0) (5:5, v/v) at a flow-rate of 0.1 ml/min. Total analysis time per sample was 18 min. The linearity of response was good (r=0.999) over the concentration range of 5–200 ng/ml. The within-day and day-to-day precision (CV) and inaccuracy were less than 3.7% and 3.8%, respectively. The mean recovery was 96.5±2.4% with the detection limit of 2 ng/ml. 相似文献
16.
C. A. J. Hajee N. Haagsma 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1995,669(2)
A rapid HPLC method with solid-phase extraction (SPE) clean-up for malachite green (MG) and leucomalachite green (LMG) in eel plasma was developed. MG and LMG were extracted with a buffered methanolic solution. The extract was subjected to aromatic sulphonic acid SPE. MG and LMG were eluted from the SPE column with methanol after a treatment with ammonia gas. The reconstituted eluate was analyzed on a Chromspher B column with acetonitrile-ion-pair buffer (ph 4.0) (6:4, v/v) as the mobile phase and detection at 610 nm after post column oxidation with PbO2. The average recoveries for MG and LMG over the linear range of applicability (20–2500 ng/ml) were 82±1% and 83±1%, respectively. The limits of quantification were 5.0 μg/1 for MG and 0.9 μ/1 for LMG. 相似文献
17.
Alwin D. R. Huitema Matthijs M. Tibben Thomas Kerbusch J. Jantien Kettenes-van den Bosch Sjoerd Rodenhuis Jos H. Beijnen 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2000,745(2)
A simple and selective assay for the determination of the alkylating cyclophosphamide metabolite phosphoramide mustard (PM) in plasma was developed and validated. PM was determined after derivatisation by high-performance liquid chromatography (HPLC) with ultraviolet detection at 276 nm. Sample pre-treatment consisted of derivatisation of PM with diethyldithiocarbamate (DDTC) at 70°C for 10 min, followed by extraction with acetonitrile in the presence of 0.7 M sodium chloride. Phase separation occurred due to the high salt content of the aqueous phase. The HPLC system consisted of a C8 column with acetonitrile–0.025 M potassium phosphate buffer, pH 8.0, (32:68, v/v) as the mobile phase. The entire sample handling procedure, from collection at the clinical ward until analysis in the laboratory, was optimised and validated. Calibration curves were linear from 50 to 10 000 ng/ml. The lower limit of quantification and the limit of detection (using a signal-to-noise ratio of 3) were 50 and 40 ng/ml, respectively, using 500 μl of plasma. Within-day and between-day precisions were below 11% over the entire concentration range and the accuracies were between 100 and 106%. PM was found to be stable at −30°C for at least 10 weeks both in plasma and as a DDTC-derivative in a dry sample. A pharmacokinetic pilot study in two patients receiving 1000 mg/m2 CP in a 1-h infusion demonstrated the applicability of the assay. 相似文献
18.
S Hartmann O Froescheis F Ringenbach R Wyss F Bucheli S Bischof J Bausch U.-W Wiegand 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,751(2):939
A HPLC method with automated column switching and UV detection is described for the simultaneous determination of retinol and major retinyl esters (retinyl palmitate, retinyl stearate, retinyl oleate and retinyl linoleate) in human plasma. Plasma (0.2 ml) was deproteinized by adding ethanol (1.5 ml) containing the internal standard retinyl propionate. Following centrifugation the supernatant was directly injected onto the pre-column packed with LiChrospher 100 RP-18 using 1.2% ammonium acetate–acetic acid–ethanol (80:1:20, v/v) as mobile phase. The elution strength of the ethanol containing sample solution was reduced by on-line supply of 1% ammonium acetate–acetic acid–ethanol (100:2:4, v/v). The retained retinol and retinyl esters were then transferred to the analytical column (Superspher 100 RP-18, endcapped) in the backflush mode and chromatographed under isocratic conditions using acetonitrile–methanol–ethanol–2-propanol (1:1:1:1, v/v) as mobile phase. Compounds of interest were detected at 325 nm. The method was linear in the range 2.5–2000 ng/ml with a limit of quantification for retinol and retinyl esters of 2.5 ng/ml. Mean recoveries from plasma were 93.4–96.5% for retinol (range 100–1000 ng/ml) and 92.7–96.0% for retinyl palmitate (range 5–1000 ng/ml). Inter-assay precision was ≤5.1% and ≤6.3% for retinol and retinyl palmitate, respectively. The method was successfully applied to more than 2000 human plasma samples from clinical studies. Endogenous levels of retinol and retinyl esters determined in female volunteers were in good accordance with published data. 相似文献
19.
Xiaoyan Chen Dafang Zhong Haiyan Xu Barbara Schug Henning Blume 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,755(1-2)
A rapid, selective and sensitive HPLC–tandem mass spectrometry method was developed and validated for simultaneous determination of flupirtine and its active metabolite D-13223 in human plasma. The analytes and internal standard diphenhydramine were extracted from plasma samples by liquid–liquid extraction, and chromatographed on a C18 column. The mobile phase consisted of acetonitrile–water–formic acid (60:40:1, v/v/v), at a flow rate of 0.5 ml/min. Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI). The method has a limit of quantitation of 10 ng/ml for flupirtine and 2 ng/ml for D-13223, using 0.5-ml plasma sample. The linear calibration curves were obtained in the concentration range of 10.0–1500.0 ng/ml for flupirtine and 2.0–300.0 ng/ml for D-13223. The intra- and inter-run precision (RSD), calculated from quality control (QC) samples was less than 7.2% for flupirtine and D-13223. The accuracy as determined from QC samples was less than 5% for the analytes. The overall extraction recoveries of flupirtine and D-13223 were determined to be about 66% and 78% on average, respectively. The method was applied for the evaluation of the pharmacokinetics of flupirtine and active metabolite D-13223 in volunteers following peroral administration. 相似文献
20.
Lauro Misael del Rivero Helgi Jung Rafael Castillo Alicia Hernndez-Campos 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1998,712(1-2)
This paper describes a high-performance liquid chromatographic method with ultraviolet absorbance detection at 304 nm for the determination of 6-chloro-5-(1-naphthyloxy)-2-methylthio benzimidazole (αBIOF10) — a new fasciolicide agent — and its sulphoxide (SOαBIOF10), in plasma and urine. It requires 2 ml of biological fluid, an extraction using Sep-Pak cartridges, and methanol for drug elution. Analysis is performed on a μBondapak C18 (10 μm) column, using methanol–acetonitrile–water (40:30:30, v/v) as the mobile phase. Results showed that the assay is sensitive: 12 ng/ml for αBIOF10 and SOαBIOF10 in plasma and 3.6 ng/ml for both compounds in urine. The response was linear between 0.195 and 12.5 μg/ml. Maximum intra-day coefficient of variation was 5.3%. Recovery obtained was 97.8% for both αBIOF10 and SOαBIOF10. In urine, recovery was 99.6% and 93.1% for αBIOF10 and SOαBIOF10 respectively. The method was used to perform a preliminary pharmacokinetic study in two sheep and was found to be satisfactory. 相似文献