Comparative study on the main active components of Baoyuan decoction in plasma and urine of normal and heart failure rats.

The global morbidity and mortality of heart failure has been increasing in recent years. Traditional Chinese medicine (TCM) was increasingly used to treat cardiovascular diseases. Baoyuan decoction (BYD) was a famous classical prescription in China. Modern pharmacological studies showed that it had obvious therapeutic effects on cardiovascular diseases, but its pathological pharmacokinetic studies were unclear. In this research, the absorption of 16 bioactive components in plasma and the excretion of 9 representative components in urine of control rats and isoproterenol (ISO)-induced heart failure rats were studied using the large-volume direct-injection LC-MS method established by our research group. The results indicated that flavonoid constituents exhibited quicker absorption and elimination than saponin constituents after oral administration of BYD. The half-life period of some bioactive compounds in the model group was increased, which contributed to the longer therapeutic effect. The cumulative excretion rate of major flavonoid components of BYD decreased significantly in the ISO-induced heart failure rats.

Evaluation of the effects of notoginseng total saponins (NS), safflower total flavonoids (SF), and the combination of NS and SF (CNS) on the activities of cytochrome P450 enzymes using a cocktail method in rats.

Notoginseng total saponins (NS), safflower total flavonoids (SF), and the combination of NS and SF, namely CNS, are used for the treatment of cardiovascular diseases in clinic. This study developed a cocktail assay involving seven cytochrome P450 (CYP) enzymes to elucidate the effect of NS, SF, and CNS on CYP enzymes and to explore the synergistic effect of CNS in terms of CYP enzymes. Ultra-performance liquid chromatography-MS and reverse-transcription polymerase chain reaction were applied to detect the activities and mRNA expression levels of CYP enzymes. SF exhibited inhibitory effects on CYP1A2, 2B1, 2E1, and 2C11 and induction effects on CYP2C19 and 2D4. NS exhibited induction effects on CYP1A2, 2B1, 2E1, 2C11, 2C19, and 2D4. CNS exhibited induction effects on CYP1A2, 2B1, 2E1, 2C19, and 2D4 and inhibitory effects on CYP3A1 in vivo. Moreover, mRNA expression results were consistent with pharmacokinetic results. Potential herb-drug interactions should be studied closely when SF, NS, or CNS with clinical drugs are metabolized by CYP1A2, 2B1, 2E1, 2C11, 2C19, 2D4, and 3A1. CNS could change the inhibition or induction effects of CYP compared to the NS group, which might be one of the causes for the synergistic effects of the combination of NS and SF.

Development and validation of an LC-MS/MS method for the determination of a novel thienoquinolin urea transporter inhibitor PU-48 in rat plasma and its application to a pharmacokinetic study.

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 C18 column (100 × 2.1 mm, 3 µm) at 35°C. The mobile phase consisted of acetonitrile and water with 0.05% formic acid added with a gradient elution at flow rate of 0.3 mL/min. Samples were detected with the triple-quadrupole tandem mass spectrometer with multiple reaction monitoring mode via electrospray ionization source in positive mode. The retention time were 6.2 min for PU-48 and 7.2 min for megestrol acetate (internal standard, IS). The monitored ion transitions were mass-to-charge ratio (m/z) 289.1 → 229.2 for PU-48 and m/z 385.3 → 267.1 for the internal standard. The calibration curve for PU-48 was linear over the concentration range of 0.1-1000 ng/mL (r2 > 0.99), and the lower limit of quantitation was 0.1 ng/mL. The precision, accuracy and stability of the method were validated adequately. The developed and validated method was successfully applied to the pharmacokinetic study of PU-48 in rats.

Effects of crystalline state and self-nanoemulsifying drug delivery system (SNEDDS) on oral bioavailability of the novel anti-HIV compound 6-benzyl-1-benzyloxymethyl-5-iodouracil in rats.

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. The plasma concentrations of W-1 were measured by high performance liquid chromatography (HPLC). The results indicated that W-1 compound were presented as crystalline forms, A and B, the degree of crystallization in form B was higher than that in form A. The SNEDDS of W-1 displayed a significant increase in the dissolution rate than W-1 powder. Furthermore, after oral administration of W-1 (100 mg/kg), the pharmacokinetic parameters of form A, form B, and W-1 SNEDDS were as follows: AUC0-t 526.4 ± 123.5, 305.1 ± 58.5 and 2297 ± 451 ng h/mL (p < .05, when W-1 SNEDDS were compared with either form A or form B), respectively. With SNEDDS formulation, the relative bioavailabilities were enhanced by 4.36-fold and 7.53-fold over the form A and form B of W-1, respectively. In conclusion, the present results suggested that the crystalline states of W-1 might lead to the lower oral bioavailability, and SNEDDS formulation is a promising strategy of improving bioavailability, in spite of that crystalline states usually carry small lot-to-lot variability.

Identification of cytochrome P450s involved in the metabolism of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1) using human recombinant enzymes and rat liver microsomes in vitro.

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. The parent drug of W-1 was incubated with rat liver microsomes (RLMs) or recombinant CYPs (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, and CYP3A5, respectively) in the presence or absence of nicotinamide adeninedinucleotide phosphate (NADPH)-regenerating system. The metabolites of W-1 were analyzed with liquid chromatography-ion trap-time of flight-mass spectrometry (LC-IT-TOF-MS). 3. The parent drug of W-1 was metabolized in a NADPH-dependent manner in RLMs. The kinetic parameters of prototype W-1 including Km, Vmax, and CLint were 2.3 µM, 3.3 nmol/min/mg protein, and 1.4 mL/min/mg protein, respectively. Two metabolites M1 and M2 were observed in shorter retention times (2.988 and 3.188 min) with a higher molecular ion at m/z 463.0160 (both M1 and M2) than that of the W-1 parent drug (6.158 min with m/z 447.0218). The CYP selective inhibition and recombinant enzymes also showed that two hydroxyl metabolites M1 and M2 are mainly mediated by CYP2C19 and CYP3A4. 4. The identification of CYPs involved in W-1 biotransformation is important to understand and minimize, if possible, the potential of drug-drug interactions.

Development and validation of a high performance liquid chromatography method for determination of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1), a novel non-nucleoside reverse transcriptase inhibitor and its application to a pharmacokinetic study in rats.

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 1.0 mL/min. The ultraviolet (UV) detector was set at the absorption wavelength of 284 nm. The calibration curve for W-1 was linear over the concentration range of 0.01-8 µg/mL and the lower limit of quantification was 10 ng/mL. The intra- and inter-day precision and accuracy were <8.9 and 5.3%, respectively. The extraction recoveries ranged from 97.9 to 101.6%. The validated HPLC method was successfully applied to a pharmacokinetic study of W-1 in rats.

Palmitoylation of PKCδ by ZDHHC5 in hypothalamic microglia presents as a therapeutic target for fatty liver disease.

The hypothalamus plays a fundamental role in controlling lipid metabolism through neuroendocrine signals. However, there are currently no available drug targets in the hypothalamus that can effectively improve human lipid metabolism. In this study, we found that the antimalarial drug artemether (ART) significantly improved lipid metabolism by specifically inhibiting microglial activation in the hypothalamus of high-fat diet-induced mice. Mechanically, ART protects the thyrotropin-releasing hormone (TRH) neurons surrounding microglial cells from inflammatory damage and promotes the release of TRH into the peripheral circulation. As a result, TRH stimulates the synthesis of thyroid hormone (TH), leading to a significant improvement in hepatic lipid disorders. Subsequently, we employed a biotin-labeled ART chemical probe to identify the direct cellular target in microglial cells as protein kinase Cδ (PKCδ). Importantly, ART directly targeted PKCδ to inhibit its palmitoylation modification by blocking the binding of zinc finger DHHC-type palmitoyltransferase 5 (ZDHHC5), which resulted in the inhibition of downstream neuroinflammation signaling. In vivo, hypothalamic microglia-specific PKCδ knockdown markedly impaired ART-dependent neuroendocrine regulation and lipid metabolism improvement in mice. Furthermore, single-cell transcriptomics analysis in human brain tissues revealed that the level of PKCδ in microglia positively correlated with individuals who had hyperlipemia, thereby highlighting a clinical translational value. Collectively, these data suggest that the palmitoylation of microglial PKCδ in the hypothalamus plays a role in modulating peripheral lipid metabolism through hypothalamus-liver communication, and provides a promising therapeutic target for fatty liver diseases.

Identification and characterization of quinoline alkaloids from the root bark of Dictamnus dasycarpus and their metabolites in rat plasma, urine and feces by UPLC/Qtrap-MS and UPLC/Q-TOF-MS.

Quinoline alkaloids are the main bioactive and potentially toxic constituents in the root bark of Dictamnus dasycarpus Turcz. (BXP), a widely used traditional Chinese medicine for the treatment of skin inflammation, eczema and rubella. However, the comprehensive analysis of the chemical components and metabolites of quinoline alkaloids remain unclear. In this study, an integrated strategy by combining UPLC/Q-TOF-MS and UPLC/Qtrap-MS was established to comprehensively profile the quinoline alkaloids from BXP and their metabolites in rat plasma, urine and feces. Q-TOF-MS (MSE mode), Qtrap-MS (EMS, MIM, pMRM and NL mode) were performed for acquiring more precursor ions and clearer precursor product ions. A step-by-step manner based on the diagnostic fragment ions (DFIs), in-house database, ClogP value and dipole moment (µ) was proposed to overcome the complexities due to the similar fragmentation behaviors of the quinoline alkaloids. As a result, a total of 73 quinoline alkaloids were unambiguously or tentatively identified. Among them, 4 furoquinolines, 10 dihydrofuroquinolines, 2 pyranoquinolinones, 4 dihydropyranoquinolinones and 9 quinol-2-ones were characterized in BXP for the first time. Moreover, a total of 98 BXP-related constituents (including 57 prototypes and 41 metabolites) were detected in rat plasma, urine and feces. The metabolic pathways included phase I reactions (O-demethylation, hydroxylation and 2,3-olefinic epoxidation) and phase II reactions (conjugation with glucuronide, sulfate and N-acetylcysteine). In conclusion, the integrated strategy with the proposed stepwise manner is suitable for rapid identifying and characterizing more extensive quinoline alkaloids of BXP in vitro and in vivo. Moreover, the results will be helpful for revealing the pharmacological effective substances or toxic substances of BXP and provide a solid basis for further research.

A Novel System for Evaluating the Inhibition Effect of Drugs on Cytochrome P450 Enzymes in vitro Based on Human-Induced Hepatocytes (hiHeps).

Cytochrome P450 (CYP) is the most important phase I drug-metabolizing enzyme, and the effect of drugs on CYP enzymes can lead to decreased pharmacological efficacy or enhanced toxicity of drugs, but there are many deficiencies in the evaluation models of CYP enzymes in vitro. Human-induced hepatocytes (hiHeps) derived from human fibroblasts by transdifferentiation have mature hepatocyte characteristics. The aim was to establish a novel evaluation system for the effect of drugs on CYP3A4, 1A2, 2B6, 2C9, and 2C19 in vitro based on hiHeps. Curcumin can inhibit many CYP enzymes in vitro, and so the inhibition of curcumin on CYP enzymes was compared by human liver microsomes, human hepatocytes, and hiHeps using UPLC-MS and the cocktail method. The results showed that the IC50 values of CYP enzymes in the hiHeps group were similar to those in the hepatocytes group, which proved the effectiveness and stability of the novel evaluation system in vitro. Subsequently, the evaluation system was applied to study the inhibitory activity of notoginseng total saponins (NS), safflower total flavonoids (SF), and the herb pair of NS-SF on five CYP enzymes. The mechanism of improving efficacy after NS and SF combined based on CYP enzymes was elucidated in vitro. The established evaluation system will become a powerful tool for the research of the effect of drugs on the activity of CYP enzymes in vitro, which has broad application prospects in drug research.

Rapid identification, isolation, and evaluation on anti-neuroinflammatory activity of limonoids derivatives from the root bark of Dictamnus dasycarpus.

A total of 49 limonoids derivatives were rapidly identified by UNIFI software and three new limonoids derivatives, named dasycarinone (1, DAS), isodictamdiol C (2) and dasycarinone A (3), along with nineteen known compounds, were isolated from the root bark of Dictamnus dasycarpus, named as "Baixianpi" in Chinese. Their structures were elucidated on the basis of spectroscopic data (UV, IR, HR-ESI-MS, NMR, CD spectra and OR). All the compounds were tested for anti-inflammatory activities by suppressing the nitric oxide (NO) production in lipopolysaccharide (LPS) induced BV-2 cells. DAS exhibited a strong anti-inflammatory activity with IC50 value of 1.8 µM. Nuclear Factor kappa B (NF-κB) luciferase assay and enzyme-linked immune sorbent assay indicated that DAS can suppress the release of inflammatory cytokines such as Tumor Necrosis Factor α (TNF-α), interleukin 6 (IL-6) via inactivating NF-κB signaling pathways. Moreover, we found that anti-inflammatory activities of obacunone-class are better than those of limonin-class by analyzing structure-activity relationship. Our results suggested that obacunone derivatives play an important role on anti-inflammation of Baixianpi. As a representative among them, DAS showed a strong anti-inflammatory activity via suppressing NF-κB signaling pathways.

Comparative study on metabolic profiling and excretion in rat bile between combination of notoginseng total saponins and safflower total flavonoids and its individual extracts by LC-MS/MS.

The combination of notoginseng total saponins (NS) and safflower total flavonoids (SF), namely CNS, presents a synergistic protection effect on the myocardial ischemia rats. The aim of this study was to find the clues for their synergistic actions by comparing the biliary metabolism and excretion profiles after oral administration of CNS and its individual extracts. An ultra-performance liquid chromatography coupled with hybrid triple quadrupole-linear ion trap mass spectrometer (UPLC-QTRAP-MS/MS) platform was used to identify and quantify the CNS-derived components in bile. The neutral losses, precursor ions, and predictive multiple reaction monitoring (pMRM) scans were firstly used to detect the CNS-derived ingredients in vivo. A total of 43 components, including 38 flavonoids and 5 ginsenosides were tentatively identified according to the previously established chemical and metabolic profiles of NS and SF. Afterwards, the primary circulating and biological components, hydroxysafflor yellow A (HSYA), ginsenosides Rg1 (GRg1), Re (GRe), and Rd (GRd) were chosen to compare the bile excretion between CNS and its individual extract groups, by using a validated LC-MRM-MS/MS method. The approach was proved to be well satisfied the related requirements from the guidelines of FDA (specificity, calibration curve, sensitivity, precision, accuracy, matrix effect, recovery, and stability). Comparing with the SF and NS groups, the combination group did not affect the metabolic pathways of the CNS-related components, however, it decreased the cumulative excretion ratios of HSYA, GRg1, GRe, and GRd. In conclusion, the compatibility of SF and NS could reduce the bile excretion of the CNS-derived compounds, which may be one of the reasons for the enhancement of anti-myocardial ischemia after combination.

Pharmacokinetics study of 16 representative components from Baoyuan Decoction in rat plasma by LC-MS/MS with a large-volume direct injection method.

BACKGROUND: Baoyuan decoction (BYD), a well-known traditional Chinese medicine (TCM) formula, is clinically used for the treatment of aplastic anemia, chronic renal failure, coronary heart disease, etc. PURPOSE: The purpose of this study was to develop a large-volume direct injection liquid chromatography-mass spectrometry (LC-MS) method for simultaneous determination of 16 representative flavonoids and saponins in rat plasma after oral administration of BYD. METHODS: The rat plasma sample was injected directly into a pre-column, which was eluted firstly by 0.05% formic acid in water. Then, the accumulated components were eluted from the pre-column and transferred into a Waters BEH C18 column with acetonitrile and water system (contain 0.05% formic acid) as the mobile phase at a rate of 0.3 ml/min. The detection was accomplished in a negative mode using the schedule multiple-reaction monitoring (sMRM). RESULTS: The correlation coefficients for calibration curves were all higher than 0.9920 for formononetin, ononin, calycosin, liquiritigenin, isoliquiritigenin, glycyrrhizic acid, glycyrrhetinic acid, liquiritin, isoliquiritin, liquiritin apioside, isoliquiritin apioside, ginsenoside Rb1, ginsenoside Re, ginsenoside Rd, ginsenoside Rg1 and astragaloside. The intra- and inter-day precisions (RSD) and accuracy (RE) for the investigated components were in the range of -10.9 to 13.7%. The average recoveries were in the range of 75.7-108.6%. This method was successfully applied to investigate the pharmacokinetics of 16 compounds of BYD in rats. The absorption and elimination rates of the representative saponins were significantly slower than most of the targeted-flavonoids after oral administration of BYD in rats. CONCLUSION: The results demonstrated that the large-volume direct injection LC-MS method provided a rapid and efficient approach for multi-components pharmacokinetics of TCM.

Pharmacokinetics, Tissue Distribution and Excretion of a Novel Diuretic (PU-48) in Rats.

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. After oral administration of PU-48 (3, 6, and 12 mg/kg, respectively) in self-nanomicroemulsifying drug delivery system (SNEDDS) formulation, the peak plasma concentrations (Cmax), and the area under the curve (AUC0⁻∞) were increased by the dose-dependent and linear manner, but the marked different of plasma half-life (t1/2) were not observed. This suggests that the pharmacokinetic profile of PU-48 prototype was first-order elimination kinetic characteristics within the oral three doses range in rat plasma. Moreover, the prototype of PU-48 was rapidly and extensively distributed into thirteen tissues, especially higher concentrations were detected in stomach, intestine, liver, kidney, and bladder. The total accumulative excretion of PU-48 in the urine, feces, and bile was less than 2%. This research is the first report on disposition via oral administration of PU-48 in rats, and it provides important information for further development of PU-48 as a diuretic drug candidate.

Comparative Study on Excretive Characterization of Main Components in Herb Pair Notoginseng-Safflower and Single Herbs by LC⁻MS/MS.

The herbal medicine combination of notoginseng-safflower has been commonly used clinically for the prevention and treatment of cardiovascular diseases. A reliable liquid chromatography-tandem mass spectrometry (LC⁻MS/MS) method was developed for simultaneous determination of six bioactive components (hydroxysafflor yellow A, notoginsenoide R1, ginsenoside Rb1, Re, Rd, and Rg1) in rat urine and feces after oral administration of notoginseng total saponins (NS), safflower total flavonoids (SF), and the combination of NS and SF (CNS). The chromatographic separation was achieved on a Waters HSS T3 column under gradient elution with acetonitrile and water containing formic acid as the mobile phase. The calibration curves were linear, with correlation coefficient (r) > 0.99 for six components. The intra- and interday precision (RSD) and accuracy (RE) of QC samples were within -14.9% and 14.9%, respectively. The method was successfully applied to study of the urinary and fecal excretion of six bioactive constituents following oral administration of NS, SF, and CNS in rats. Compared to the single herb, the cumulative excretion ratios of six constituents were decreased in the herbal combination. The study indicated that the combination of notoginseng and safflower could reduce the renal and fecal excretion of the major bioactive constituents and promote their absorption in rats.

Interaction between 3,4­dichlorophenyl­propenoyl­sec.­butylamine (3,4­DCPB), an antiepileptic drug, and cytochrome P450 in rat liver microsomes and recombinant human enzymes in vitro.

The compound 3,4­dichlorophenyl­propenoyl­sec.­butylamine (3,4­DCPB) is an antiepileptic drug. The purpose of the present research was to identify cytochrome P450 (CYP450) responsible for the metabolism of 3,4­DCPB and evaluate the effects of 3,4­DCPB on the activities of CYP450 enzymes. 3,4­DCPB was incubated with rat liver microsomes (RLMs) plus six CYP450 enzyme-specific inhibitors, or six recombinant human CYP450 enzymes (rhCYP450s). The concentrations of 3,4­DCPB and six CYP450 enzyme-activities probe drugs were detected by high-performance liquid chromatographic (HPLC). The results showed that the prototype of 3,4­DCPB was metabolized by multiple CYP450 enzymes into three metabolites, and the predominant isoforms were CYP2D6 (metabolite M1), CYP1A2 (M2), CYP2C19 and CYP3A4 (M3), respectively., in the presence of ß-NADPH (1 mM) in RLMs or rhCYP450s. Compared with the control (PB-), phenobarbital pre-treatment (PB+) significantly enhanced levels (all of p < 0.01) of hydroxylmethytobutamide (CYP2C9), 4­hydroxy­mephenytoin (CYP2C19), acetaminophen (CYP1A2), 6­hydroxychlorzoxazone (CYP2E1) and oxidized nifedipine (CYP3A4), respectively, in spite of dextrophan (CYP2D6) was not markedly enhanced in RLMs. Conversely, the inhibitory ratios of 3,4­DCPB (16 µg/mL, 59 µM) on the activities of CYP2C9, CYP2C19, CYP1A2 and CYP2D6 were 97.6%, 59.0%, 53.5% and 36.5%, respectively. However, CYP2E1 (both of PB- and PB+) and CYP3A4 (PB+) were not inhibited by 3,4­DCPB in RLMs. In conclusion, the present study showed that 3,4­DCPB was metabolized by multiple CYP450 enzymes. 3,4­DCPB inhibited the activities of CYP2C9, CYP2C19, CYP1A2 and CYP2D6, rather than that CYP2E1 and CYP3A4 enzymes, suggesting that the different effects of 3,4­DCPB on the CYP450 enzymes might influence metabolic drug-drug interaction in antiepileptics therapy.

Effects of Baoyuan decoction, a traditional Chinese medicine formula, on the activities and mRNA expression of seven CYP isozymes in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Baoyuan decoction (BYD), a traditional Chinese medicine (TCM) formula, is composed of four herbs and widely used with western drugs to treat coronary heart disease, aplastic anemia and chronic renal failure in clinic. However, no study of the effect of BYD on the cytochrome P450 (CYP) activities has been reported. AIM OF THE STUDY: The purpose of the present study was to evaluate the potential influences of BYD on the activities of seven CYP isozymes (CYP1A2, 2B6, 2C9, 2C19, 2D6, 2E1, and 3A4) in rats. MATERIALS AND METHODS: A sensitive and selective UPLC-MS/MS method for simultaneous determination of seven probe drugs and internal standard (IS) in rat plasma was developed and validated. The influence of BYD on the activities of CYP isozymes and mRNA expression levels were carried out by comparing plasma pharmacokinetics and real-time reverse transcription-polymerase chain reaction (RT-PCR) of probe drugs between control and BYD treatment groups respectively. RESULTS: The calibration curve were linear, with correlation coefficient (r) > 0.99 for seven probe drugs. The intra and inter-assay accuracy and precision of the method were within ±â€¯14.9% and the recoveries ranged from 83.2% to 106.1%. Compared with control group, BYD at low (1.46 g/kg) and high (7.30 g/kg) dosages could significantly increase Cmax and AUC0-t of chlorzoxazone and testosterone, while decrease AUC0-t of phenacetin at high dosage and increase AUC0-t of tolbutamide and metoprolol. Additionally, BYD had increased AUC0-t of bupropion at low dosage and decreased it at high dosage. The mRNA expression results were in accordance with those of pharmacokinetic. CONCLUSION: BYD exhibited inhibitory effects on CYP2C9, CYP2E1, and CYP3A4. Moreover, BYD had induction effects on CYP1A2, and CYP2D6 activities. However, no significant change in CYP2C19 activity was observed. It would be useful for the safe and effective usage of BYD in clinic.

Profile of disposition, tissue distribution and excretion of the novel anti-human immunodeficiency virus (HIV) agent W-1 in rats.

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. After oral administration of W-1 (50, 100 and 200 mg/kg, respectively) in self-microemulsifying drug delivery system formulation, the pharmacokinetic parameters of W-1 were as follows: the peak plasma concentrations (C max) were 0.42, 1.50 and 2.55 µg/mL, the area under the curve (AUC0-t) were 0.89, 2.27 and 3.96 µg/h mL and the plasma half-life (t 1/2) were 5.15, 3.77 and 3.77 h, respectively. Moreover, the prototype of W-1 was rapidly and extensively distributed into fifteen tissues, especially higher concentrations were detected in intestine, stomach and liver, respectively. The plasma protein binding of W-1 in rat, beagle dog and human were in the range of 97.96-99.13 %. This study suggested that W-1 has an appropriate pharmacokinetics in rats, such as rapid absorption, moderate clearance, and rapid distribution to multiple tissues. Those properties provide important information for further development W-1 as an anti-HIV-1 drug candidate.

Quantitative and qualitative analysis of the novel antitumor 1,3,4-oxadiazole derivative (GLB) and its metabolites using HPLC-UV and UPLC-QTOF-MS.

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. The calibration curve for GLB was linear at 300 nm. The lower limit of quantification was 10 ng/mL. The precision, accuracy and stability of the method were validated adequately. This method was successfully applied to the pharmacokinetic study in rats for detection of GLB after oral administration. Moreover, the structures of parent compound GLB and its two major metabolites M1 and M2 were identified in plasma using an ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight- mass spectrometry (UPLC-ESI-QTOF-MS) method. Our results indicated that the di-hydroxylation (M1) and hydroxylation (M2) of GLB are the major metabolites. In conclusion, the present study provided valuable information on an analytical method for the determination of GLB and its metabolites in rats, can be used to support further developing of this antitumor agent.