A high-performance liquid chromatography-electrospray ionization-mass spectromentry (LC–ESI–MS) method has been developed for the determination of picroside II in dog plasma. Plasma samples were deproteinated with acetonitrile and a Hypersil ODS2 column was used with a mobile phase consisted of methanol-water. The determination was validated in the concentration range of 0.10–50 μg mL−1 using 50 μL of plasma. The method was successfully applied to a pharmacokinetic study of picroside II.
相似文献This study describes an accurate, sensitive, and specific chromatographic method for the simultaneous quantitative determination of lamivudine and zidovudine in human blood plasma, using stavudine as an internal standard. The chromatographic separation was performed using a C8 column (150 × 4.6 mm, 5 μm), and ultraviolet absorbency detection at 270 nm with gradient elution. Two mobile phases were used. Phase A contained 10 mM potassium phosphate and 3% acetonitrile, whereas Phase B contained methanol. A linear gradient was used with a variability of A-B phase proportion from 98–2% to 72–28%, respectively. The drug extraction was performed with two 4 mL aliquots of ethyl acetate.
相似文献Gabapentin is an anticonvulsant drug used for the treatment of epilepsy. It is not bound to plasma protein and is not metabolized. A high performance liquid chromatography–mass spectrometric micro method is described in this report for its determination from human plasma. Chromatography was performed on a 50 × 4.6 mm, 4 μm nitrile column and the parent ion detected in the positive ionization mode on single quadrupole analyzer (Q1MI) with atmospheric pressure ionization source. Extraction was carried out on C18, 100 mg/3cc cartridge using 10 μL sample volume. The mean extraction recovery was 97% and within batch and between batch coefficients of variation were <9%. Lack of interference from endogenous substances helped in achieving a highly sensitive method without the need for monitoring fragment ions. The lowest concentration injected on column for calibration curve was 195 pg (range 0.5–64 ng). The method was applied for analysis of samples from a cross-over bio-equivalence study comparing two formulations.
相似文献An LC–UV screening method for simultaneous determination of ascorbic acid (C), and the free forms of thiamine (B1) riboflavin (B2), niacin (B3), pyridoxine (B6) in enriched food products was developed and validated. The chromatographic separation was accomplished within 18 min using a gradient of water with 0.1% formic acid (pH 2.5) and methanol with 0.1% formic acid on a C18 reverse phase column (5 μm, 150 × 3.2 mm) while detection was performed at two wavelengths (266 and 290 nm). Sample preparation was based on an extraction method originally developed for vitamin C. This procedure besides extracting vitamin C was extended to the extraction of the free forms of vitamins B1, B2, B3, B6 and B9. The developed analytical method was successfully applied for the simultaneous determination of the vitamin C content along with the free vitamin B forms of three different enriched food products.
相似文献A rapid and sensitive LC-MS method has been developed for the determination of luteolin-7-O-β-d-glucoside in rat plasma after solvent extraction. Separation was on an Elite Hypersil ODS2 column (250 mm × 4.6 mm i.d., 5 μm) with a mobile phase of acetonitrile-0.3% acetic acid (26:74, v/v). The samples were analyzed by using positive electrospray ionization MS in selected ion monitoring mode. The selected ions for luteolin-7-O-β-d-glucoside and the internal standard, isoquercitrin, were m/z 448.95 and m/z 464.95. Good linearity was observed over the range of 20–2,000 ng mL−1 with a lower limit of quantification of 20 ng mL−1. No interference peaks or matrix effects were observed. The validated method was applied to the pharmacokinetic study of luteolin-7-O-β-d-glucoside in rat plasma after intravenous administration of Kudiezi Injection.
相似文献A sensitive and specific LC–MS-MS method is described for the simultaneous quantification of risperidone and 9-hydroxyrisperidone in human plasma. After extraction with tert-butyl methyl ether, plasma samples were separated on an Atlantis HILIC Silica C18 column (4.6 × 150 mm, 5 μm)with a mobile phase of ammonium formate buffer (10 mM, pH 4.0)/acetonitrile (40/60, v/v). Detection was by MS-MS. The method was fully validated according to the accuracy profile theory. It is based on β-expectation tolerance interval for the total measurement error which includes trueness and intermediate precision. The measurement uncertainty derived from β-expectation tolerance interval was estimated at each of the validation standards. The linearity fitted well over the range of 0.11–26.75 ng mL−1 for risperidone with an LLOQ of 0.11 ng mL−1, and for 9-hydroxyrisperidone, at a range of 0.15–37.8 ng mL−1 with an LLOQ of 0.15 ng mL−1. The intra- and inter-batch precision of risperidone were <5.71 and 8.22%, respectively. For 9-hydroxyrisperidone, the data were 5.78 and 6.48%. The recoveries were 88.78% (risperidone) and 70.35% (9-hydroxyrisperidone). The developed method was applied to a pharmacokinetic study of risperidone.
相似文献A sensitive and simple HPLC method with fluorimetric detection has been developed for determination of droperidol in pharmaceutical tablets, human serum, and human milk. Chromatography was performed on a 100 mm × 3 mm i.d. C18 column with methanol–water, 30:70 (v/v), pH 3.5, as mobile phase at a flow-rate of 0.8 mL min−1. The injection volume was 5 μL and detection was by monitoring emission at 324 nm after excitation at 283 nm. Droperidol and p-hydroxybenzoic acid (internal standard) eluted after 5.3 and 6.1 min, respectively. The method was validated over the concentration range 1.14 × 10−7 to 9.12 × 10−6 M. Selectivity was good and the limits of detection and quantitation of the method were approximately 3.54 × 10−8 and 1.07 × 10−7 M, respectively, corresponding to 13 and 40 ng mL−1. The applicability of the method to determination of droperidol in pharmaceuticals, human serum, and human milk was demonstrated.
相似文献Solid-phase extraction (SPE) and reversed-phase liquid chromatography (RP-LC) have been used for simple, sensitive simultaneous analysis of cyromazine and melamine residues in liquid milk and eggs. The conditions used for SPE and LC were investigated and optimized. A combined cation-exchange–reversed-phase cartridge was used for clean-up, and an ODS (C18) column (150 mm × 4.6 mm i.d., 5-μm particles) with 62:38 (v/v) 5 mm sodium lauryl sulfate (pH 3.4)–acetonitrile as mobile phase was used for RP-LC. Under the optimum conditions the method limit of detection (LOD) for both cyromazine and melamine was 6.2 μg kg−1 for liquid milk samples, and 11.5 μg kg−1 for egg samples. Average recovery of cyromazine and melamine from milk samples was 90.3%, RSD 4.6–5.6%, and 99.6%, RSD 3.2–4.7%, respectively. Average recovery of cyromazine and melamine from egg samples was 85.3%, RSD 1.0–4.7%, and 89.6%, RSD 3.1–5.0%, respectively. The method enables detection of melamine and cyromazine at levels as low as 20.7 μg kg−1 in liquid milk and 38.3 μg kg−1 in egg.
相似文献We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were prepared from magnetite (Fe3O4) as the magnetic component, paracetamol as the template, methacrylic acid as a functional monomer, and 2-(methacrylamido) ethyl methacrylate as a cross-linker. The m-MIPs were then characterized by transmission electron microscopy, FT-IR spectroscopy, X-ray diffraction and vibrating sample magnetometry. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples. Following its elution from the column loaded with the m-MIPs with an acetonitrile-buffer (9:1) mixture, it was submitted to HPLC analysis. Paracetamol can be quantified by this method in the 1 μg L−1 to 300 μg L−1 concentration range. The limit of detection and limit of quantification in plasma samples are 0.17 and 0.4 μg L−1. The preconcentration factor of the m-MIPs is 40. The HPLC method shows good precision (4.5 % at 50 μg L−1 levels) and recoveries (between 83 and 91 %) from spiked plasma samples.
We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples
A new, specific and sensitive high performance liquid chromatography analytical procedure was developed and validated for the determination of TM208 in rat primary solid organs/tissues and plasma. TM208 was extracted from the appropriate matrix using methanol followed by centrifugation at 11,255×g for 20 min and injection of a 30 μL aliquot. Separation was carried out under gradient conditions using an ODS C18 column equipped with a guard column. The mobile phase consisted of methanol and water and retention times of TM208 and plunarizine (IS) were 17.658 and 26.175 min, respectively. The analytical procedure provided acceptable precision, accuracy, recoveries and linearity. Stability studies showed that TM208 was stable in organs/tissues homogenates for three freeze–thaw cycles, at room temperature for at least 24 h 3 weeks at −20 °C. The validated method was successfully applied to the determination of TM208 in SD rats following oral administration at a dose of 250 mg kg−1.
相似文献The present paper describes the development of a reversed phase liquid chromatographic method for advanced intermediate of rabeprazole sodium (RBS-1) in the presence of its impurities. Successful separation of RBS-1 from the synthetic impurities achieved on a Inertsil ODS3V C18, 150 mm × 4.6 mm column. The developed LC method was validated with respect to linearity, accuracy, precision, specificity and ruggedness. To the best of our knowledge, a validated stability indicating LC method which separates all the impurities disclosed in this investigation was not published elsewhere.
相似文献Liquid chromatography combined with electrospray ionization tandem mass spectrometry positive ion mode is used for the determination of glimepiride in human plasma. Gliclazide was used as the internal standard. The chromatographic separation was performed on a ACE 5 C18, 50 × 4 mm, 5 μm column at 30 °C with mobil phase consisting of 200 mL water, 450 mL acetonitrile, 350 mL methanol, 0.6 mL glacial acetic acid with a 0.5 mL min−1 flow rate. The work-up procedure involved a liquid–liquid extraction of the compounds. Mass spectrometric data were acquired in single ion monitoring of the ions 324.11 > 127.25 and 491.16 > 352.08 for glimepiride and gliclazide, respectively. The method was validated in the concentration range of 5–1,000 ng mL−1. Retention times of glimepiride and gliclazide were 1.65 and 1.36 min, respectively. The run time was 2.5 min. The method was found suitable to analyse human plasma samples for application in pharmacokinetic, pharmacodynamic, bioavailability/bioequivalance studies.
相似文献A sensitive, specific and rapid high-performance liquid chromatography method was developed for determination of 5,6,7,8,3′,4′-hexamethoxy-3-sulfonyl flavone in rat plasma. A simple methanol-induced protein precipitation was applied to extract 5,6,7,8,3′,4′-hexamethoxy-3-sulfonyl flavone and Picroside II (the internal standard) from rat plasma. Chromatographic separation was achieved on a Hypersil ODS2 analytical column (200 mm × 4.6 mm, 5 μm) with acetonitrile–0.04% triethylamine solution (adjusted to pH 5.8 using phosphoric acid) (24:76, v/v) as mobile phase. The calibration curves were linear over the range of 0.2–40 μg mL−1. Absolute recoveries of 5,6,7,8,3′,4′-hexamethoxy-3-sulfonyl flavone were 82.7–95.9% from rat plasma. The intra- and inter-day relative standard deviation precisions were less than 5 and 9%, respectively. The method was successfully applied to the pharmacokinetic study of 5,6,7,8,3′,4′-hexamethoxy-3-sulfonyl flavone in rats after intravenous administration.
相似文献A heart-cut two-dimensional high-performance liquid chromatography method for enantiomeric determination of salbutamol, salmeterol and atenolol in urine is presented. It involves the use of two separations in a liquid chromatography–liquid chromatography achiral–chiral coupling. Target compounds were previously separated in a primary column (Kinetex™ HILIC, 2.6 μm, 150 × 2.1 mm I.D.) with a mixture of MeOH:ACN:ammonium acetate buffer (5 mM, pH 6) 90:5:5 (v/v/v) as mobile phase at a flow rate of 0.40 mL min−1. Enantiomeric separation was carried out by transferring peak of each compound through a switching valve to a vancomycin chiral column (Chirobiotic™ V, 2.6 μm, 150 × 2.1 mm I.D.) using MeOH:ammonium acetate buffer (2 mM, pH 4) 97:3 (v/v) as mobile phase at a flow rate of 0.50 mL min−1. Ultraviolet detection was done at 227 nm. The method was applied to determine target analytes in urine samples after enzymatic hydrolysis with β-glucuronidase from Helix pomatia, followed by a solid-phase extraction procedure using Isolute® HCX mixed-mode cartridges. Extraction recoveries ranged from 82 to 90 % in urine samples. Detection limits were 0.091–0.095 μg for each enantiomer of atenolol and between 0.058 and 0.076 and 0.18–0.14 μg for enantiomers of salbutamol and salmeterol, respectively (3 mL of urine). Linearity ranges were between 0.5 and 10 μg mL−1. Intraday and interday reproducibilities of enantiomeric ratio and enantiomeric fraction, expressed as relative standard deviation, were between 1.9 and 9.0 %. The optimized method was successfully applied to the analysis of urine samples obtained from excretion studies in volunteers and in freeze-dried urine samples, containing urinary components with MW < 10,000 and components with MW > 10,000, spiked with different amounts of studied drugs.
相似文献A rapid, sensitive and specific method for the simultaneous quantification of resibufogenin (RBG) and 3-epi-resibufogenin (3-ERBG) in rat plasma was developed by using a liquid–liquid extraction procedure and liquid chromatography–electrospray ionization/tandem mass spectrometric (LC–ESI–MS/MS) analysis. The separation was performed by HPLC on a reversed phase C18 HPLC column (150 × 2.1 mm, 3.5 μm) using a mobile phase of acetonitrilel-0.1% formic acid aqueous solution (45:55, v/v). The determination was performed by a triple-quadrupole mass spectrometer in the multiple reaction monitoring using positive mode of electrospray ionization (ESI). The calibration curves were both linear (R > 0.995) over the concentration range of 3.0–5,000 ng mL−1, and the lower limits of quantification were 3.0 ng mL−1 for both RBG and 3-ERBG. The intra-day and inter-day precisions (% RSD) were all less than 15%, and the accuracies (%RE) were within the range of ±15%. The mean recoveries of RBG, 3-ERBG and IS were over 82.7, 84.8 and 90.0% (n = 6), respectively. The method was proved to be rapid, sensitive and specific, and has been successfully applied to determine RBG and its major metabolite 3-ERBG in rat plasma after oral administration of RBG for pharmacokinetic study. Comparison of pharmacokinetic data with anti-tumor activities of RBG and ERBG suggested that 3-ERBG, as a major metabolite of RBG in rats, was perhaps also a bioactive form of RBG in vivo.
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