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ABSTRACT: A specific and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometric method was developed for the quantification of imatinib and its primary metabolite N-desmethyl imatinib in human plasma. Protein precipitation with methanol was used for sample preparation. High-performance liquid chromatographic separation was performed on a Thermo BDS Hypersil C18 column (4.6 × 100 mm, 2.4 µm) with methanol-water (55:45, v/v) containing 0.1% formic acid and 0.2% ammonium acetate as the mobile phase, using isocratic elution at a flow rate of 0.7 mL/min. Detection was conducted with positive electrospray ionization multiple reaction monitoring of the ion transitions at m/z 494 → 394 for imatinib, 480 → 394 for N-desmethyl imatinib and 297 → 110 for the internal standard (palonosetron). The assay was validated in the concentration ranges of 8-5,000 ng/mL for imatinib and 3-700 ng/mL for N-desmethyl imatinib. The quantification limits for imatinib and N-desmethyl imatinib were 8 and 3 ng/mL, respectively. The intra-day and inter-day precision values of the assay (expressed as percentage relative standard deviation) were less than 15% at all concentration levels within the tested range, and the accuracy values were between 85 and 115%. The established method was successfully applied to the pharmacokinetic study of imatinib mesylate capsules in 24 healthy Chinese volunteers.
Journal of chromatographic science 04/2013; · 0.88 Impact Factor
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ABSTRACT: To determine the cardioprotective effect of magnesium lithospermate B (MLB) on myocardial ischemia/reperfusion (MI/R) injury and to investigate the antioxidant potential in vivo and in vitro.
MI/R injury was induced by the occlusion of left anterior descending coronary artery for 30 min followed by reperfusion for 3 h in rats. After reperfusion, hearts were harvested to assess infarct size, histopathological damages, the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH) and malondialdehyde (MDA). Blood samples were collected to determine serum levels of creatine kinase-MB (CK-MB), cardiac troponin (cTnl) and lactate dehydrogenase (LDH). Furthermore, simulated ischemia/reperfusion (SI/R) injury in vitro was established by oxygen and glucose deprivation (OGD) for 2 h followed by 24-hour recovery period in cardiomyocytes. The activity of LDH in the cultured supernatant and the levels of intracellular reactive oxygen species (ROS), SOD and MDA in cardiomyocytes were also measured. Finally, cardiomyocytes apoptosis was determined with flow cytometry.
MLB significantly limited infarct size, ameliorated histopathological damages and prevented leakage of CK-MB, cTnI and LDH. Additionally, SOD, CAT, GPx and GSH activities were notably increased by MLB, along with the MDA content decreased as compared with the model group in rats. In vitro study, MLB also decreased LDH activity in the cultured supernatant, increased SOD activity in cardiomyocytes, reduced intracellular ROS and MDA levels, and significantly suppressed cardiomyocytes apoptosis.
MLB possessed remarkably cardioprotective effects on MI/R injury in vivo and in vitro. The protection of MLB may contribute to its antioxidant properties.
Journal of Traditional Chinese Medicine 02/2013; 33(1):85-91. · 0.30 Impact Factor
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Yi Ding,
Wenxing Liu,
Yan Yan Jia,
Chengtao Lu,
Xin Jin,
Jing Yang,
Yanrong Zhu,
Lin Yang,
Ying Song,
Likun Ding, Aidong Wen
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ABSTRACT: In this study, the authors compared the effects of amlodipine (AML) on the bioavailability of cephalexin (LEX) and cefuroxime axetil (CXM). Twenty-four healthy men were randomized to 4 treatments according to a crossover design with a 14-day washout. After an overnight fast, they were administered orally LEX 500 mg alone, LEX 500 mg 2 hours after oral administration of AML 5 mg, CXM 500 mg alone, and CXM 500 mg 2 hours after oral administration of AML 5 mg. All participants completed the whole study without side effects being observed. Pharmacokinetic data were analyzed by noncompartmental modeling with WinNonlin software. The geometric mean (GM) ratios were 1.38 (90% confidence interval [CI], 1.32-1.45) for the area under the concentration-time curve (AUC) for LEX and 1.27 (1.18-1.36) for the maximum concentration of drug in serum (C(max) ) for LEX followed by AML versus alone. In contrast, no significant differences were found in the pharmacokinetic parameters of CXM between treatments (P < .05). They authors conclude that AML possesses an enhancement effect in β-lactam antibiotic bioavailability (in this case, LEX), and this interaction may be specific to the peptidomimetic β-lactam antibiotics.
The Journal of Clinical Pharmacology 01/2013; 53(1):82-6. · 2.91 Impact Factor
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ABSTRACT: Sometimes, drugs and their metabolites in plasma may convert to each other. This phenomenon is called interconversion, which may result in the instability problem of the plasma samples. The instability problem caused by interconversion of the co-existing metabolites may often be ignored, since there is no drug metabolite in the quality control samples prepared for method validation. Pitavastatin lactone (Pi-LAC), a main metabolite of pitavastatin (Pi), is very unstable and easily converted to Pi in plasma. In this paper, simple and rapid LC-ESI-MS/MS methods were developed for the simultaneous determination of Pi and Pi-LAC in human plasma and urine. The sample stability was examined under different conditions. The interconversion of Pi and Pi-LAC was prevented by adding a pH 4.2 buffer solution to the freshly collected plasma samples. Detection was performed using an electrospray ionization (ESI) operating in positive ion multiple reaction monitoring mode by monitoring the ion transitions from m/z 422.2→290.3 (Pi), 404.2→290.3 (Pi-LAC) and m/z 611.3→423.2 (candesartan cilextetil, the internal standard), respectively. The calibration curve of Pi and Pi-LAC in both human plasma and urine showed good linearity over the concentration range of 0.1-200ng/mL. The established methods were successfully applied to a pharmacokinetic study of pitavastatin calcium tablets in healthy Chinese volunteers after oral administration of 1, 2 and 4mg single and multiple doses of pitavastatin calcium. The pharmacokinetic parameters of Pi and Pi-LAC in Chinese volunteers were given respectively. The urinary excretion profiles of Pi and Pi-LAC in Chinese volunteers were also presented. After receiving a single 4mg oral dose of pitavastatin calcium, the average cumulative urinary excretion percentages of Pi and Pi-LAC in Chinese volunteers were (0.41±0.16)% and (6.1±5.0)%, respectively.
Journal of pharmaceutical and biomedical analysis 01/2013; 72:8-15. · 2.45 Impact Factor
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ABSTRACT: Myocardial ischemia/reperfusion (MI/R) injury, in which inflammatory response plays a vital role, is frequently encountered in clinical practice. The present study was aimed to investigate the anti-inflammatory effect and the possible mechanism of protocatechuic aldehyde (PAl) on MI/R injury both in vivo and in vitro. The rat model of MI/R injury was induced by ligation of the left anterior descending coronary artery for 30 min, followed by 3-h reperfusion, and pretreatment with PAl could protect the heart from MI/R injury by reducing myocardial infarct size and the activities of creatine kinase-MB and cardiac troponin I (cTn-I) in serum. Also, PAl administration markedly reduced cellular injury induced by simulated ischemia/reperfusion (SI/R) in cultured neonatal rat cardiomyocytes, which was evidenced by increased cell viability, reduced lactate dehydrogenase and cTn-I activities in the culture medium, and greatly decreased percentage of cell apoptosis. Moreover, the levels of tumor necrosis factor-α, interleukin-6, intracellular adhesion molecule-1, phosphorylated IκB-α, and the nuclear translocation of nuclear factor-kappa B (NF-κB) were all evidently decreased by PAl both in vivo and in vitro. Taken together, these observations suggested that PAl could exert great protective effects against MI/R injury in rats and SI/R injury in cultured neonatal rat cardiomyocytes, and the cardioprotective mechanism might be involved in the suppression of inflammatory response via inhibiting the NF-κB signaling pathway.
Inflammation 12/2012; · 1.75 Impact Factor
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ABSTRACT: Phytochemical investigation of the whole plants of Clematis tangutica led to the isolation of three new triterpenoid saponins (1-3), together with four known saponins (4-7). Their structures were determined by extensive spectral analysis and chemical evidences. Compounds 1-7 were evaluated for their cardioprotective activities in cardiomyocytes anoxia/reoxygenation (A/R) model. The results showed that those saponins exhibited cardioprotective effects by decreasing the levels of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH).
Fitoterapia 12/2012; · 1.85 Impact Factor
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Ying Yin,
Yue Guan,
Jialin Duan,
Guo Wei,
Yanrong Zhu,
Wei Quan,
Chao Guo,
Dan Zhou,
Yanhua Wang,
Miaomiao Xi, Aidong Wen
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ABSTRACT: Danshensu, as the effective components of Salvia miltiorrhiza (Danshen), has been widely used in clinic for treatment of cardiovascular diseases in China. In the present study, we aimed to confirm the cardioprotective effect of Danshensu from myocardial ischemia/reperfusion (MI/R) injury in vivo, and investigate the potential molecular mechanisms against simulated ischemia/reperfusion (SI/R) induced cardiomyocytes apoptosis in vitro. The rat model of MI/R injury was induced by a transient vessel occlusion for 30 minutes and reperfusion for 3 hours, Danshensu significantly reduced myocardium infarct size and the production of creatine kinase-MB (CK-MB), cardiac troponin (cTnI) in serum. In vitro experiment, H9c2 cardiomyocytes was incubated with vehicle or ischemic buffer during hypoxia, and then it was reoxygenated with or without Danshensu. Danshensu markedly improved cell viability and decreased lactate dehydrogenase (LDH) release. We confirmed anti-apoptotic effect of Danshensu both by flow-cytometric analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and this effect was associated with the increase of Bcl-2/Bax ratio and the decrease of active caspase-3 expression. Western blot analysis also showed that Danshensu increased phosphorylation of Akt and extracellular signal-related kinase 1/2 (ERK1/2) in H9c2 cells, and the protective effects of Danshensu were partially inhibited by phosphatidylinositol 3'-kinase (PI3K) specific inhibitor wortmannin or ERK specific inhibitor U0126. Our results suggested that Danshensu could provide significant cardioprotection against MI/R injury, and the potential mechanisms might be attributed to against cardiomyocytes apoptosis through activating the PI3K/Akt and ERK1/2 signaling pathways.
European journal of pharmacology 11/2012; · 2.59 Impact Factor
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ABSTRACT: We have developed a series of new C(10) dipeptide stationary phases via a simple and effective synthetic method. The preparation of the new phases involves the synthesis of silanes and the surface modification of silica. Chromatographic evaluations of these columns were performed using the Engelhardt, Tanaka, and Neue test mixtures. The applicability of these new stationary phases was also evaluated using a series of diagnostic probes including acids, bases or neutral compounds and several generic applications. These new C(10) dipeptide stationary phases showed excellent hydrolytic stability over a wide pH range. Like other existing amide-embedded columns, these new stationary phases exhibit higher retention for polar and hydrophilic compounds and different selectivity as compared to conventional C(18) columns. These new phases are compatible with 100% aqueous mobile phases, and also provide high column efficiency and good peak shapes for both acidic and basic compounds.
Journal of chromatography. A 11/2012; · 4.19 Impact Factor
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ABSTRACT: ETHNOPHARMACOLOGICAL RELEVANCE: Tibetan medicine get used to use the flowers of Gentiana straminea Maxim. to cure inflammation of stomach and intestines, hepatitis, cholecystitis, etc. The flowers of Gentiana macrophylla Pall. have been traditionally treated as an anti-inflammatory agent to clear heat in Mongolian medicine. In traditional Chinese medicine, Gentiana macrophylla Pall. and Gentiana straminea Maxim. have also been used under the name "Gentianae Macrophyllae Radix" and prescribed for the treatment of pain and inflammatory conditions. AIM OF STUDY: The present study evaluated the pharmacological effects of two species of "Radix Gentianae Macrophyllae" in experimental inflammation and pain models, and determined the chemical compounds that may correlate with their pharmacological activities. The comparison is needed to identify whether the two related plants can be used interchangeably. MATERIALS AND METHODS: We evaluated the pharmacological effects of the flowers of Gentiana macrophylla Pall. and Gentiana straminea Maxim. in experimental inflammation and pain models. An HPLC-MS method was developed to analyze the chemical composition. The effects of Gentiana macrophylla Pall. and Gentiana straminea Maxim. on the p65 and p50 phosphorylation were examined by immunblotting. NF-κB transcriptional activity was measured using the luciferase assay, in vitro kinase assay and Griess reaction. RESULTS: The extracts of Gentiana macrophylla Pall. and Gentiana straminea Maxim. possessed significant antinociceptive and anti-inflammatory activities. Flavonoids, secoiridoid glycosides and triterpines were determined in the extracts and may be the basis of the observed pharmacological effects. Nuclear translocation of p65, p50 and NF-κB transcriptional activity induced by LPS were suppressed by Gentiana macrophylla Pall. and Gentiana straminea Maxim. CONCLUSION: The results clearly demonstrated that the chemical composition and pharmacological activities of the two herbs were similar, which support the interchangeability among the two herbs when using them in folk medicine.
Journal of ethnopharmacology 10/2012; · 2.32 Impact Factor
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ABSTRACT: A highly selective and sensitive liquid chromatographic tandem mass spectrometric (LC-MS–MS) method was developed and validated
for the quantitation and pharmacokinetic study of niacin (NA) and its two metabolites niacinamide (NAM) and nicotinuric acid
(NUR) in human plasma. Protein precipitation with 14% perchloric acid solution was selected for sample preparation, and ganciclovir
was used as an internal standard. Separation was on a Phenomenex Curosil-PFP (250mm×4.6mm, 5μm) column by a multiple
steep steps linear gradient elution with mobile phase consisting of water and methanol, both containing 0.1% formic acid,
pumped at a flow rate of 1mLmin−1. The determination was optimized and carried out with positive electrospray ionization by selective multiple reaction monitoring.
The method was linear in the concentration range of 15–2,000ngmL−1 for NA, 70–2,000ngmL−1 for NAM and 10–2,000ngmL−1 for NUR, by standard addition calibration. The application of LC-MS–MS was demonstrated for the specific and quantitative
analysis of NA, NAM and NUR in human plasma from a pharmacokinetic study in 12 healthy Chinese volunteers treated with three
incremental doses of niacin extended-release/lovastatin tablets and an additional steady-state regime.
KeywordsColumn liquid chromatography-Mass spectrometry-Pharmacokinetics-Niacin, niacinamide and nicotinuric acid
Chromatographia 04/2012; 72(3):245-253. · 1.20 Impact Factor
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ABSTRACT: Tenofovir dipivoxil fumarate (9-[(R)-2-[[bis (pivaloyloxymethoxy) phosphinoyl] methoxy] propyl] adenine fumarate) is a novel ester prodrug of tenofovir. It has been developed as an anti-hepatitis B virus clinical candidate. The purpose of this study was to determine the pharmacokinetic parameters of tenofovir dipivoxil fumarate (test) and the commercially available tenofovir disoproxil fumarate (Viread®, reference). In addition, the bioavailability of tenofovir dipivoxil fumarate was evaluated in healthy male fasted subjects after a single comparatively equivalent dose.
This single-dose, randomized, two-way, open-label, crossover study was conducted at Xijing Hospital, Xi'an, China. The study drug was administered under fasted conditions. Serial blood samples were obtained over 72 hours after oral administration of each treatment. Bioavailability of the drug was assessed in accordance with the State Food and Drug Administration bioequivalence criteria.
Eighteen subjects were enrolled and completed the study, with all study treatments being generally well tolerated. The geometric mean ratios (90% confidence interval [CI]) for maximum plasma concentration (C(max)), area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUC(last)), and area under the plasma concentration-time curve from time zero extrapolated to infinity (AUC(∞)) were 124.49% (90% CI 115.85, 133.79), 122.85% (90% CI 115.55, 130.62), and 122.43% (90% CI 115.71, 129.54), respectively.
The relative bioavailability of tenofovir dipivoxil was 20% higher compared with tenofovir disoproxil fumarate; this result was consistent with the preclinical data.
Clinical Drug Investigation 03/2012; 32(5):333-8. · 1.82 Impact Factor
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Yi Ding,
ChengTao Lu,
Jing Yang,
Xin Jin,
Lin Yang,
Chao Wang,
ZongYing Ma,
YanRong Zhu,
LiKun Ding,
YanYan Jia, AiDong Wen
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ABSTRACT: Felotaxel (SHR110008), currently under clinical investigation in phase I trial, is a new effective taxane with greater anticancer activity and less toxicity than docetaxel. Pharmacokinetic studies in animal models are the important components in clinical development of this agent. In this study, a rapid and sensitive analytical method based on high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of felotaxel in tumor-bearing mice plasma, urine, feces and tissues (brain, heart, liver, lung and kidney and tumor). For all matrices, sample preparation involved liquid-liquid extraction with ethyl acetate. Calibration curves (1/x² weighted) offered satisfactory linearity (r² ≥ 0.995) within the test range. The lower limit of quantitation (LLOQ) for all matrices was 10 ng/ml except that for mouse plasma and brain LLOQ was 1 ng/ml. The accuracy and precision ranged from 86.1 to 107.2% and 1.1 to 9.2%, respectively. Recoveries (73.9-96.1%) and matrix effects (76.4-97.2%) were satisfactory in all the biological matrices examined. Stability studies (85.1-101.5%) showed that felotaxel was stable both during the assay procedure and long-term storage. The assay was successfully applied to plasma pharmacokinetics, tissue distribution and excretion study of mice. The pharmacokinetic parameters, such as half-life, mean residence time, maximum concentration were determined. The preclinical data are useful for the design of clinical trials of felotaxel.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 03/2012; 887-888:61-6. · 2.78 Impact Factor
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ABSTRACT: The purpose of this study was to assess the potential inhibitory and inductive effects of felotaxel on cytochrome P450 isozymes in vitro. The inhibitory effects of felotaxel on various CYP isozymes were determined in human liver microsomes. In addition, the ability of felotaxel to induce CYP enzymes in cultured human hepatocytes was evaluated. Results showed that felotaxel did not inhibit CYP1A2-, CYP2C9-, CYP2C19-, CYP2E1-, CYP2D6-, CYP2B6-, CYP2C8-, and mediated activities in human liver microsomes up to a concentration of 100 μM, while the inhibition (<30% inhibition) of CYP3A4 activities was observed at 100 μM felotaxel. In vitro felotaxel did not induce CYP1A2, CYP2C19, or CYP3A4/5 activities in cultured human hepatocytes. In present study, felotaxel has been identified as a potent inhibitor of metabolic activity of CYP3A4. Therefore, clinically relevant pharmacokinetic drug-drug interactions are likely to occur between felotaxel and co-administered substrates of these CYP3A4 isozymes. These findings provided some useful information for safe and effective use of felotaxel in clinical practice.
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie 02/2012; 66(4):318-21. · 2.24 Impact Factor
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ABSTRACT: Carbamazepine (CBZ) is a commonly prescribed antiepileptic drug. Adverse effects and drug-drug interaction are the two major concerns for its clinic application. CBZ is mainly metabolized by cytochrome P450 (CYP) 3A4, a strong inducer of CYP3A4 as well, which in turn influences the pharmaceutical profiles of the co-administrated drugs. To date, little is known about the mechanisms underlying CBZ-induced CYP3A4 expression. In this study, we explored the possible roles of Pregnane X receptor (PXR) and the histone deacetylase 1 (HDAC1) on the CBZ-induced CYP3A4 expression. The results showed that: (1) Although the expression of PXR was increased in CBZ treated cells, PXR gene silencing surprisingly showed no significant effects on CBZ-induced CYP3A4 expression; (2) CBZ inhibited the binding of HDAC1 to the promoter of CYP3A4. In addition, both dominant negative form and siRNA of HDAC1 could repress the CBZ-induced CYP3A4 expression. These data, for the first time indicate that HDAC1, is required for the CBZ-induced CYP3A4 expression.
Journal of pharmaceutical and biomedical analysis 01/2012; 58:78-82. · 2.45 Impact Factor
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ABSTRACT: The carbon tetrachloride (CCl(4))-treated model involving mature Sprague-Dawley rats has been historically relied upon to study liver injury and regeneration and to test drug efficacy and disposition. However, there few studies about phase II metabolic enzymes changes in CCl(4)-model rats. The metabolic and excretion tests of phenacetin and acetaminophen (APAP), and the mRNA test of cytochrome P4501A2 (CYP1A2) and phase II metabolic enzymes [sulfotransferase 1A1 (SULT1A1) and UDP-glucuronosyltransferase 1A6 (UGT1A6)] were studied in model rats after CCl(4) pretreatment. The result showed that the function and structure of liver and kidney was impaired by CCl(4) pretreatment, and a significant difference has been observed in the mRNA content of CYP1A2 (p<0.01) in model group, but there was no significant difference on the mRNA content of SULT1A1 and UGT1A6 in both groups. Compared to the control group, a significant higher content of phenacetin (p<0.01) and sulfate-APAP (AS, p<0.01) was observed in the metabolic tests of phenacetin and APAP. Statistically significant differences in cumulative urinary excretion levels of APAP, AG and AS for CCl(4) model rats were observed also. We have shown that impaired disposition of probe drugs in this model was due to both liver and kidney dysfunction in CCl(4)-model rats and we should consider the development of a new liver damage model without renal impairment.
Environmental toxicology and pharmacology. 01/2012; 33(3):453-8.
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ABSTRACT: Felotaxel (SHR110008), currently under clinical investigation in phase I trial, is a new taxane with potent antitumor effects. The purpose of this research was to evaluate the pharmacokinetic profiles of felotaxel in rats and the protein binding in plasma. Data were collated from several preclinical investigations, where the plasma pharmacokinetics, tissue distribution and excretion of felotaxel were assessed after a single intravenous (i.v.) injection (5 mg/kg) to rats. Samples felotaxel concentration was determined by a LC-MS/MS method. The plasma concentration versus time data was analyzed non-compartmental model. Plasma protein binding was assessed using ultrafiltration. Pharmacokinetic properties of felotaxel were similar to the previous data from the rats. Felotaxel was rapidly distributed to normal tissues, drug concentrations in the tissues tested except the brain were two to eight times higher than those in plasma, but half-lives and mean residence times were similar. The kidneys manifested as the dominant organs with high exposure that might be responsible for elimination of felotaxel. Approximately 0.21% and 0.72% of felotaxel was excreted via the urine and feces within 24 h; 0.25% was excreted into the bile up to 12 h after a single dose. The protein binding ability of felotaxel with concentration 100-5000 ng/mL in the plasma was nearly linear. This study first provided the full absorption, distribution, and excretion characteristics of felotaxel, which would be helpful for its clinical regiment design.
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie 12/2011; 66(2):98-102. · 2.24 Impact Factor
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ABSTRACT: A sensitive liquid chromatography-mass spectrometric method was developed for the quantification of ipriflavone in human plasma. The method utilized liquid-liquid extraction of plasma with ethyl acetate. A gradient elution was performed on a Hedera ODS-2 column (150×2.1 mm i.d., 5 µm), using a mobile phase consisting of 0.1% formic acid solution and methanol at a flow rate of 0.5 mL/min. The single quadrupole mass spectrometer was operated in selected-ion monitoring mode via positive electrospray ionization interface detecting m/z 239.1 and 285.1 for ipriflavone and diazepam (the internal standard), respectively. To improve the selectivity and sensitivity, the fragment ion m/z 239.1, which was produced by in-source collision-induced dissociation, was chosen as the quantitative ion for ipriflavone. The method was fully validated and applied to a pharmacokinetic study of ipriflavone. After oral administration of a single 200 mg ipriflavone tablet, the C(max,) AUC(0-72 h) , t(1/2) and T(max) were 6.3±6.3 ng/mL, 80.0±69.1 µg h/L, 23.0±8.6 h and 3.4±2.1 h, respectively.
Biomedical Chromatography 05/2011; 26(1):123-8. · 1.97 Impact Factor
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ABSTRACT: ErbB2 receptor (HER2) tyrosine kinase was overexpressed in about 25% breast cancers, and was correlated with extremely aggressive phenotype and poor prognosis. Lapatinib, an oral, reversible inhibitor of both ErbB2 and EGFR tyrosine kinases, was approved in combination with capecitabine for treating advanced stage ErbB2 positive breast cancers. However, the clinical response of Lapatinib was seriously limited by the drug resistance. We established the Lapatinib resistant breast cancer cell lines and the preliminary data demonstrated the increased autophagosome formation in the stable resistant cells. The resistant cells were re-sensitized to Lapatinib after treated with autophagy inhibitor. According to our preliminary data and related reference, we hypothesized that autophagy could facilitate the ErbB2 positive breast cancer cells to be Lapatinib resistant and promoted the survival of the resistant cells. The abrogation of autophagy might restore the drug sensitivity. Autophagy might be one of the targets to overcome the Lapatinib resistance.
Medical Hypotheses 05/2011; 77(2):206-8. · 1.39 Impact Factor
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ABSTRACT: A simple, rapid and accurate liquid chromatography-tandem mass spectrometry method has been developed. After a liquid-liquid extraction procedure, samples were chromatographed on an Agilent TC-C(18) (150 × 4.6 mm, 5 μm) column using an isocratic elution mobile phase composed of methanol and distilled water (70:30, v/v) at a flow rate of 0.5 mL/min. After single-dose administration of 0.5, 1 and 2 mg metolazone, the t(1/2) values were 6.6 ± 2.8, 7.9 ± 1.2 and 7.6 ± 1.9 h, respectively. The pharmacokinetic parameters of multiple doses (1 mg metolazone) were as follows: t(1/2) was 8.9 ± 1.0 h; C(max) was 22.4 ± 5.0 ng/mL; and AUC(0-48) was 156.8 ± 31.6 ng h/mL.
Biomedical Chromatography 03/2011; 25(10):1138-43. · 1.97 Impact Factor
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ABSTRACT: A sensitive and rapid LC-MS/MS method was developed and validated for the determination of levamisole in human plasma. The assay was based on liquid-liquid extraction of analytes from human plasma with ethyl ether. Chromatographic separation was carried on an Agilent HC-C(8) column (150 mm × 4.6 mm, 5 μm) at 40°C, with a mobile phase consisting of acetonitrile-10 mM ammonium acetate (70:30, v/v), a flow rate of 0.5 mL/min and a total run time of 6 min. Detection and quantification were performed by mass spectrometry in the multiple reaction monitoring mode with positive electrospray ionization m/z at 205.1→178.2 for levamisole, and m/z 296.1→264.1 for mebendazole (internal standard). The assay was linear over a concentration range of 0.1-30 ng/mL with a lower limit of quantification of 0.1 ng/mL. The coefficient of variation of the assay precision was less than 8.5%. The assay was successfully used to analyze human plasma samples in a pharmacokinetic study where levamisole was administered as a liniment.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 02/2011; 879(5-6):299-303. · 2.78 Impact Factor
