Publications by authors named "Ya-qing Lou"

Methyl 3-amino-6-methoxythieno [2,3-b] quinoline-2-carboxylate (PU-48) is a novel diuretic urea transporter inhibitor. The aim of this study is to investigate the profile of plasma pharmacokinetics, tissue distribution, and excretion by oral dosing of PU-48 in rats. Concentrations of PU-48 within biological samples are determined using a validated high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.

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The compound 3,4‑dichlorophenyl‑propenoyl‑sec.‑butylamine (3,4‑DCPB) is an antiepileptic drug. The purpose of the present research was to identify cytochrome P450 (CYP450) responsible for the metabolism of 3,4‑DCPB and evaluate the effects of 3,4‑DCPB on the activities of CYP450 enzymes.

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Mizolastine is a selective histamine H1 receptor antagonist for chronic urticaria or allergic rhinitis. We investigated whether the variant genotypes of metabolic enzymes UGT1A1, CYP3A5 and transporter ABCB1 influence pharmacokinetic phenotype of substrate mizolastine in Chinese volunteers. Genotyping of single nucleotide polymorphisms in UGT1A1*6 (G211A), CYP3A5*3 (A6986G) and ABCB1 (C3435T) was determined by the pyrosequencing method.

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A specific, sensitive and stable high-performance liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative determination of methyl 3-amino-6-methoxythieno [2,3-b]quinoline-2-carboxylate (PU-48), a novel diuretic thienoquinolin urea transporter inhibitor in rat plasma. In this method, the chromatographic separation of PU-48 was achieved with a reversed-phase C column (100 × 2.1 mm, 3 μm) at 35°C.

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The objective of this study was to investigate the effect of crystalline state and a formulation of self-nanoemulsifying drug delivery system (SNEDDS) on oral bioavailability of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1), a novel non-nucleoside reverse transcriptase inhibitor, in rats. The crystalline states of W-1 were characterized by scanning electron microscope (SEM), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). The SNEDDS was formulated by medium-chain lipids, characterized by droplet particle size.

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Background And Objectives: Pioglitazone is a thiazolidinedione antihyperglycemic drug with insulin-sensitizing properties. We investigated whether the variant genotypes of cytochrome P450 2C8 (CYP2C8), CYP2C9, CYP3A5 and transporter ABCB1 influence the pharmacokinetic phenotype of the substrate pioglitazone in Chinese individuals.

Participants And Methods: Single-nucleotide polymorphisms were determined by the PCR-restriction fragment length polymorphism method in 244 (CYP2C8 and CYP2C9) healthy Chinese Han individuals.

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1. The aim of this study was to identify the hepatic metabolic enzymes, which involved in the biotransformation of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1), a novel non-nucleoside reverse transcriptase inhibitor (NNRTI) in rat and human in vitro. 2.

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The purpose of this study was to characterize the disposition, distribution, excretion and plasma protein binding of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1) in rats. Concentrations of W-1 within biological samples were determined using a validated high performance liquid chromatography method. The plasma protein binding of W-1 was examined by equilibrium dialysis method.

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Cytochrome P450 2W1 (CYP2W1) is expressed specially in certain cancers and could metabolize some substances into cytotoxic antitumor drugs in Caucasian ethnic population. To investigate the genetic polymorphism of CYP2W1 in Chinese, all the nine exons and exon-intron junctions were sequenced by dideoxy chain termination method among 385 Chinese subjects (including 223 Han and 162 Uygur). The present results showed that 40 single nucleotide polymorphisms (SNPs) were detected (14 in the exons and 26 in the introns), 10 were novel variants of which in Chinese.

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Fructose-based 3-acetyl-2,3-dihydro-1,3,4-oxadiazole (GLB) is a novel antitumor agent and belongs to glycosylated spiro-heterocyclic oxadiazole scaffold derivative. This research first reported a simple, specific, sensitive and stable high performance liquid chromatography-ultraviolet detector (HPLC-UV) method for the quantitative determination of GLB in plasma. In this method, the chromatographic separation was achieved with a reversed phase C18 column.

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A sensitive and selective high-performance liquid chromatographic (HPLC) method for determination of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1), a novel non-nucleoside reverse transcriptase inhibitor in rat plasma, was developed and validated. Chromatographic separation of W-1 and megestrol acetate (internal standard) was achieved on a reversed-phase C18 column at 25°C. The mobile phase was consisted of acetonitrile-water (60:40, v/v) and pumped at a flow rate of 1.

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This study is to elucidate the metabolic pathway of 1,2-[bis (1,2-benzisoselenazolone-3 (2H)-ketone)]-ethane (BBSKE) in rats. Rats were administrated with a single dose of BBSKE 200 mg x kg(-1). The metabolites in rat urine, feces, bile and plasma were identified by LC-MSn analysis.

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Interindividual variability of cytochrome P450 (CYP) 3A inhibition by grapefruit juice was investigated in relation to CYP3A5 and multidrug resistance gene (MDR) 1 genetic polymorphisms in Chinese Han, Uygur, and Kazakh healthy subjects. The measurement of urinary 6 beta-hydroxycortisol/cortisol ratio was used to evaluate CYP3A activity in vivo by high-performance liquid chromatography. CYP3A5*3 and MDR1 C1236T, G2677T/A, and C3435T polymorphisms were analyzed by polymerase chain reaction restriction fragment length polymorphism.

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A rapid and sensitive liquid chromatography/electrospray ionization tandem mass spectrometric (LC/ESI-MS/MS) method has been developed to determine 1, 2-[bis(1,2-benzisoselenazolone-3(2H)-ketone)]-ethane (BBSKE), a novel antineoplastic agent, in rat plasma. The analytes were separated on a C18 column with a mobile phase of methanol-water (75:25, v/v) and detected using a triple-quadrupole mass spectrometer in positive mode with the selective reaction monitoring. The characteristic ion dissociation transitions were m/z 603.

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The purpose of the present study was to investigate the effect of Ganoderma lucidum polysaccharide (GLPS), a major active component in Chinese medicinal fungus, on cytochrome P450 metabolic activity in Bacillus Calmette Guérin (BCG)-induced immune hepatic injury in rats. The enzyme kinetics of the probes including chlorzoxazone (CYP2E1), phenacetin (CYP1A2) and nifedipine (CYP3A) were evaluated by HPLC. The results showed that BCG-pretreatment (125 mg/kg) significantly increased serum levels of alanine transaminase (ALT), nitrite and malondialdehyde (MDA), inhibited activities of superoxide dismutase (SOD) and decreased P450 total content in microsomes (p<0.

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Background: Cytokine production in the host immune response after transplantation may contribute to the variable CYP3A-dependent drug disposition. We investigated the effect of TNF-alpha, IL-10, CYP3A5 and ABCB1 polymorphisms on immunosuppressant tacrolimus pharmacokinetics in liver transplant patients.

Methods: Genetic polymorphisms in TNF-alpha, IL-10, CYP3A5 and ABCB1 were studied in 70 liver transplant recipients and 70 donors.

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This study investigated the effect of berberine on the early phase of hepatocarcinogenesis stimulated by diethylnitrosamine (DEN, 150 mg/kg, 4 weeks) plus phenobarbital (PB, 75 mg/kg, 7 days) in rats. The expressions of proliferating cell nuclear antigen (PCNA) and inducible nitric oxide synthase (iNOS) were evaluated by immunohistochemistry. The activities of CYP isoenzymes were analyzed using different probe drugs including chlorzoxazone (CYP2E1) and phenacetin (CYP1A2) by high-performance liquid chromatography (HPLC) in vivo or in vitro.

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A novel HPLC-UV method with pre-column derivatization by using 2-mercaptoethanol was established for determination of 1,2-[bis(1,2-benzisoselenazolone-3(2H)-ketone)]-ethane (BBSKE) in dog plasma. The derivatives were identified by mass spectrometry. The method had a good linear range of 0.

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The pharmacokinetics (PK) and metabolism of 3,4-dichlorophenyl-propenoyl-sec.-butylamine (3,4-DCPB), a novel antiepileptic drug, were investigated after its oral administration to rats (100 mg/kg) by HPLC. The absorption and elimination of 3,4-DCPB were rapid.

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Objective: To study the pharmacokinetics of multi-dose oral tetra-arsenic tetra-sulfide (As(4)S(4)) in acute promyelocytic leukemia (APL) patients and its major side effects.

Methods: Clinical pharmacokinetic study of As(4)S(4) was carried out in 7 patients who had never used arsenic before. The total concentration of arsenic in blood, urine and hair was determined with hydride generation-atomic absorption spectrometry.

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