Simultaneous determination of iguratimod and its metabolite in rat plasma using a UPLC-MS/MS method: Application for drug-drug interaction

This aim of the work was to establish an acceptable sensitive assay based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for quantitatively analyzing the plasma concentrations of iguratimod (IGR) and its metabolite M2 in rats, and to further investigate the effect of fluconazole on the pharmacokinetics of IGR and M2. The mobile phase consisted of acetonitrile and water with 0.1% formic acid, was used to separate IGR, M2 and internal standard (IS) fedratinib on a UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with the flow rate of 0.4 mL/min. Positive ion mode and multiple reaction monitoring (MRM) were used to construct the quantitative analysis. The calibration standard of IGR and M2 covered 2-10000 and 1-1000 ng/mL respectively, with the lower limit of quantification (LLOQ) as 2 ng/mL and 1 ng/mL respectively. In addition, selectivity, recovery, accuracy, precision, matrix effect and stability of the method validation program were well accepted in this work. Subsequently, this approach was used to assess the effect of fluconazole on the pharmacokinetics of IGR and M2 in rats. In the presence of 20 mg/kg fluconazole (experimental group), we found the main pharmacokinetic parameters were significantly altered when compared with 2.5 mg/kg IGR alone (control group). Among them, AUC(0-∞) and Cmax of IGR in the experimental group was 1.43 and 1.08 times higher than that of the control group, respectively. Moreover, we also found that the other main pharmacokinetic parameters of M2 had no significant changes, except t1/2z and Tmax. In conclusion, fluconazole significantly altered the main pharmacokinetics of IGR and M2 in rats. It implys that we should pay more attention to the adverse reaction of IGR when the concomitant use of fluconazole and IGR occur in the future clinical practice.

Differential inhibition of sildenafil and macitentan on saxagliptin metabolism

The development of diabetes mellitus (DM) is generally accompanied by erectile dysfunction (ED) and pulmonary arterial hypertension (PAH), which increases the use of combination drug therapy and the risk of drug-drug interactions. Saxagliptin for the treatment of DM, sildenafil for the treatment of ED and PAH, and macitentan for the treatment of PAH are all substrates of CYP3A4, which indicates their potential involvement in drug-drug interactions. Therefore, we investigated potential pharmacokinetic interactions between saxagliptin and sildenafil/macitentan. We investigated this speculation both in vitro and in vivo, and explored the underlying mechanism using in vitro hepatic metabolic models and molecular docking assays. The results showed that sildenafil substantially inhibited the metabolism of saxagliptin by occupying the catalytic site of CYP3A4 in a competitive manner, leading to the alterations in the pharmacokinetic properties of saxagliptin in terms of increased maximum plasma concentration (Cmax), area under the plasma concentration-time curve from time 0 to 24 h (AUC(0-t)), area under the plasma concentration-time curve from time 0 extrapolated to infinite time (AUC(0-∞)), decreased clearance rate (CLz/F), and prolonged terminal half-life (t1/2). In contrast, a slight inhibition was observed in saxagliptin metabolism when concomitantly used with macitentan, as no pharmacokinetic parameters were altered, except for CLz/F. Thus, dosage adjustment of saxagliptin may be required in combination with sildenafil to achieve safe therapeutic plasma concentrations and reduce the risk of potential toxicity, but it is not necessary for co-administration with macitentan.

Genetic variants, haplotype determination, and function of novel alleles of CYP2B6 in a Han Chinese population

Amino acid variants in protein may result in deleterious effects on enzymatic activity. In this study we investigate the DNA variants on activity of CYP2B6 gene in a Chinese Han population for potential use in precision medicine. All exons in CYP2B6 gene from 1483 Chinese Han adults (Zhejiang province) were sequenced using Sanger sequencing. The effects of nonsynonymous variants on recombinant protein catalytic activity were investigated in vitro with Sf12 system. The haplotype of novel nonsynonymous variants with other single nucleotide variants in the same allele was determined using Nanopore sequencing. Of 38 alleles listed on the Pharmacogene Variation Consortium, we detected 7 previously reported alleles and 18 novel variants, of which 11 nonsynonymous variants showed lower catalytic activity (0.00-0.60) on bupropion compared to CYP2B6*1. Further, these 11 novel star-alleles (CYP2B6*39-49) were assigned by the Pharmacogene Variation Consortium, which may be valuable for pharmacogenetic research and personalized medicine.

Effects of myricetin and quercetin on ticagrelor metabolism and the underlying mechanism

The aim of this study was to investigate the potential drug-drug interactions (DDIs) between ticagrelor and other drugs as well as their underlying mechanisms. Rat liver microsome (RLM) reaction system was used to screen potential DDIs in vitro, and ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was applied to detect the levels of ticagrelor and AR-C124910XX, the main metabolite of ticagrelor. A total of 68 drugs were screened, 11 of which inhibited the production of AR-C124910XX to 20% or less, especially two flavonoids (myricetin and quercetin). The half-maximal inhibitory concentration (IC50) of myricetin on ticagrelor was 11.51 ± 0.28 μM in RLM and 17.96 ± 0.54 μM in human liver microsome (HLM). The IC50 of quercetin in inhibiting ticagrelor in RLM and HLM was 16.92 ± 0.49 μM and 60.15 ± 0.43 μM, respectively. They all inhibited the metabolism of ticagrelor through a mixed mechanism. In addition, Sprague-Dawley (SD) rats were used to study the interactions of ticagrelor with selected drugs in vivo. We found that the main pharmacokinetic parameters including AUC (0-t), AUC (0-∞) and Cmax of ticagrelor were significantly increased when ticagrelor was combined with these two flavonoids. Our results suggested that myricetin and quercetin of flavonoids both had significant effects on the metabolism of ticagrelor, providing reference data for the clinical individualized medication of ticagrelor.

Inhibitory effects of the main metabolites of Apatinib on CYP450 isozymes in human and rat liver microsomes

PURPOSE

The inhibitory effect of Apatinib on cytochrome P450 (CYP450) enzymes has been studied. However, it is unknown whether the inhibition is related to the major metabolites, M1-1, M1-2 and M1-6.

METHODS

A 5-in-1 cocktail system composed of CYP2B6/Cyp2b1, CYP2C9/Cyp2c11, CYP2E1/Cyp2e1, CYP2D6/Cyp2d1 and CYP3A/Cyp3a2 was used in this study. Firstly, the effects of APA and its main metabolites on the activities of HLMs, RLMs and recombinant isoforms were examined. The reaction mixture included HLMs, RLMs or recombinant isoforms (CYP3A4.1, CYP2D6.1, CYP2D6.10 or CYP2C9.1), analyte (APA, M1-1, M1-2 or M1-6), probe substrates. The reactions were pre-incubated for 5 min at 37 °C, followed by the addition of NAPDH to initiate the reactions, which continued for 40 min. Secondly, IC50 experiments were conducted to determine if the inhibitions were reversible. The reaction mixture of the "+ NADPH Group" included HLMs or RLMs, 0 to 100 of μM M1-1 or M1-2, probe substrates. The reactions were pre-incubated for 5 min at 37 °C, and then NAPDH was added to initiate reactions, which proceeded for 40 min. The reaction mixture of the "- NADPH Group" included HLMs or RLMs, probe substrates, NAPDH. The reactions were pre-incubated for 30 min at 37 °C, and then 0 to 100 μM of M1-1 or M1-2 was added to initiate the reactions, which proceeded for 40 min. Finally, the reversible inhibition of M1-1 and M1-2 on isozymes was determined. The reaction mixture included HLMs or RLMs, 0 to 10 μM of M1-1 or M1-2, probe substrates with concentrations ranging from 0.25Km to 2Km.

RESULTS

Under the influence of M1-6, the activity of CYP2B6, 2C9, 2E1 and 3A4/5 was increased to 193.92%, 210.82%, 235.67% and 380.12% respectively; the activity of CYP2D6 was reduced to 92.61%. The inhibitory effects of M1-1 on CYP3A4/5 in HLMs and on Cyp2d1 in RLMs, as well as the effect of M1-2 on CYP3A in HLMs, were determined to be noncompetitive inhibition, with the Ki values equal to 1.340 μM, 1.151 μM and 1.829 μM, respectively. The inhibitory effect of M1-1 on CYP2B6 and CYP2D6 in HLMs, as well as the effect of M1-2 on CYP2C9 and CYP2D6 in HLMs, were determined to be competitive inhibition, with the Ki values equal to 12.280 μM, 2.046 μM, 0.560 μM and 4.377 μM, respectively. The inhibitory effects of M1-1 on CYP2C9 in HLMs and M1-2 on Cyp2d1 in RLMs were determined to be mixed-type, with the Ki values equal to 0.998 μM and 0.884 μM. The parameters could not be obtained due to the atypical kinetics of CYP2E1 in HLMs under the impact of M1-2.

CONCLUSIONS

M1-1 and M1-2 exhibited inhibition for several CYP450 isozymes, especially CYP2B6, 2C9, 2D6 and 3A4/5. This observation may uncover potential drug-drug interactions and provide valuable insights for the clinical application of APA.

The Pharmacokinetic Interaction of Tirabrutinib with Voriconazole, Itraconazole, and Fluconazole in SD Rats by UPLC-MS/MS

BACKGROUND

Tirabrutinib is an orally effective, approved, and highly selective second-generation Bruton's tyrosine kinase (BTK) inhibitor for the treatment of recurrent or refractory primary central nervous system lymphoma (PCNSL).

OBJECTIVE

This study aimed to develop an ultra-high performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) method for the determination of tirabrutinib concentration in rat plasma, where zanubrutinib was used as an internal standard (IS). This method was also applied to study whether tirabrutinib would interact with voriconazole, itraconazole, and fluconazole in rats, providing a reference value for clinical medication guidance.

METHODS

In the current study, the organic solvent protein precipitation method was used to treat plasma samples, which is simple and reproducible. Tirabrutinib (m/z 455.32 → 320.21) and zanubrutinib (m/z 472.13 → 455.04) were separated on a Waters Acquity BEH C18 column (2.1 × 50 mm, 1.7 μm) and detected by multiple reaction monitoring (MRM) in positive ionization mode.

RESULTS

The method showed good linearity in the range of 5-3000 ng/mL for tirabrutinib with the lower limit of quantification (LLOQ) of 5 ng/mL. The recovery and matrix effects were 85.7-91.0% and 102.0-113.3%, respectively. The accuracy, precision, stability, and carry-over effect were also acceptable. The method could also be used for determining the pharmacokinetic interaction of tirabrutinib in rats. The results showed AUC0→∞ of tirabrutinib to be increased by 139.3% and 83.9% in the presence of voriconazole and fluconazole, respectively, while itraconazole had little effect.

CONCLUSION

It is necessary to monitor the concentration of tirabrutinib in patients when it is combined with voriconazole and fluconazole to achieve a better therapeutic effect and reduce the risk of adverse reaction. Further research should be conducted in the future.

Applications of human and bovine serum albumins in biomedical engineering: A review

Serum albumin, commonly recognized as a predominant major plasma protein, is ubiquitously distributed among vertebrates, demonstrating versatility and widespread accessibility. Numerous studies have discussed the composition and attributes of human and bovine serum albumin; nonetheless, few systematic and comprehensive summaries on human and bovine serum albumin exist. This paper reviews the applications of human and bovine serum albumin in biomedical engineering. First, we introduce the differences in the structure of human and bovine serum albumin. Next, we describe the extraction methods for human and bovine serum albumin (fractionation process separation, magnetic adsorption, reverse micellar (RM) extraction, and genetic engineering) and the advantages and disadvantages of recently developed extraction methods. The characteristics of different processing forms of human and bovine serum albumin are also discussed, concomitantly elucidating their intrinsic properties, functions, and applications in biomedicine. Notably, their pivotal functions as carriers for drugs and tissue-engineered scaffolds, as well as their contributions to cell reproduction and bioimaging, are critically examined. Finally, to provide guidance for researchers in their future work, this review summarizes the current state of human and bovine serum albumin research and outlines potential future research topics.

The impacts of CYP3A4 genetic polymorphism and drug interactions on the metabolism of lurasidone

The aim of this study was to investigate the impacts of 24 variants of recombinant human CYP3A4 and drug interactions on the metabolism of lurasidone. In vitro, enzymatic reaction incubation system of CYP3A4 was established to determine the kinetic parameters of lurasidone catalyzed by 24 CYP3A4 variants. Then, we constructed rat liver microsomes (RLM) and human liver microsomes (HLM) incubation system to screen potential anti-tumor drugs that could interact with lurasidone and studied its inhibitory mechanism. In vivo, Sprague-Dawley (SD) rats were applied to study the interaction between lurasidone and olmutinib. The concentrations of the analytes were detected by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). As the results, we found that compared with the wild-type CYP3A4, the relative intrinsic clearances vary from 355.77 % in CYP3A4.15 to 14.11 % in CYP3A4.12. A series of drugs were screened based on the incubation system, and compared to without olmutinib, the amount of ID-14283 (the metabolite of lurasidone) in RLM and HLM were reduced to 7.22 % and 7.59 %, and its IC50 were 18.83 ± 1.06 μM and 16.15 ± 0.81 μM, respectively. At the same time, it exerted inhibitory effects both through a mixed mechanism. When co-administration of lurasidone with olmutinib in rats, the AUC(0-t) and AUC(0-∞) of lurasidone were significantly increased by 73.52 % and 69.68 %, respectively, while CLz/F was observably decreased by 43.83 %. In conclusion, CYP3A4 genetic polymorphism and olmutinib can remarkably affect the metabolism of lurasidone.

Development of a UPLC-MS/MS method for the determination of lacosamide and its metabolite and its application to drug-drug interaction

Lacosamide, a third-generation novel antiepileptic drug, was first approved in 2008 as an adjunct to partial seizures. In 2014, the U.S. Food and Drug Administration (FDA) approved it as a single agent for partial seizures. Since epilepsy is a chronic condition, most patients need long-term antiepileptic medicinal products, so it is even more important to consider the drug-drug interactions (DDIs). For the purpose of this experiment, an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay with accuracy and simplicity was optimized and fully validated for the simultaneous quantitative determination of lacosamide and O-Desmethyl-lacosamide (ODL), and DDIs between lacosamide and nisoldipine in vivo and in vitro was researched. The protein was precipitated with acetonitrile, the analytes were eluted with acetonitrile and a 0.1% formic acid solution in a gradient program, and lacosamide, ODL, and lamotrigine (Internal Standard, IS) were successfully separated by chromatography. The findings of the biological analysis revealed that the lower limit of quantification (LLOQ) for lacosamide in samples was 2 ng/mL and the linearity ranged from 2 to 10000 ng/mL. The LLOQ for ODL was 1 ng/mL, while the linearity range for this substance was 1-1,000 ng/mL. In rat liver microsomes (RLM), the LLOQ of ODL was 80 ng/mL and the linear range was 80-40000 ng/mL. The selectivity, stability, matrix effect and recovery rate were all satisfied with the need of quantitative analysis of samples. Then, the UPLC-MS/MS assay was employed successfully on the interactions of lacosamide and nisoldipine in vivo and in vitro. The half-maximal inhibitory concentration (IC50) was 3.412 μM in RLM, where nisoldipine inhibited the metabolism of lacosamide with a mixture of inhibition mechanism. In rat pharmacokinetic experiments, it was found that nisoldipine could significantly change the pharmacokinetic characteristics of lacosamide, including AUC(0-t), AUC(0-∞), Tmax, CLz/F and Cmax, but had no significant effect on ODL. In summary, the UPLC-MS/MS method could accurately and sensitively quantify lacosamide and ODL, and could be used for the interaction between nisoldipine and lacosamide in vivo and in vitro.

Genetic variations of CYP3A4 on the metabolism of itraconazole in vitro

Itraconazole is a triazole anti-infective drug that has been proven to prevent and treat a variety of fungal and viral infections and has been considered to be a potential therapeutic remedy for COVID-19 treatment. In this study, we aimed to completely evaluate the impacts of Cytochrome P450 3A4 (CYP3A4) variant proteins and drug interactions on the metabolism of itraconazole in recombinant insect microsomes, and to characterize the potential mechanism of substrate selectivity. Incubations with itraconazole (0.2-15 μM) in the presence/absence of lopinavir or darunavir were assessed by CYP3A4 variants, and the metabolite hydroxyitraconazole concentrations were measured by UPLC-MS/MS. Our data showed that when compared with CYP3A4.1, 4 variants (CYP3A4.9, .10, .28 and .34) displayed no significant differences, and 3 variants (CYP3A4.14, .15 and .19) exhibited increased intrinsic clearance (CLint), whereas the remaining 17 variant proteins showed decreased enzyme activities for the catalysis of itraconazole. Moreover, the inhibitory effects of lopinavir and darunavir on itraconazole metabolism varied in different degrees. Furthermore, different changed trend of the kinetic parameters in ten variants (CYP3A4.5, .9, .10, .16, .19, .24, .28, .29, .31, and .33) were observed, especially CYP3A4.5 and CYP3A4.16, and this may be related to the metabolic site-heme iron atom distance. In the present study, we functionally analyzed the effects of 25 CYP3A4 protein variants on itraconazole metabolism for the first time, and provided comprehensive data on itraconazole metabolism in vitro. This may help to better assess the metabolism and elimination of itraconazole in clinic to improve the safety and efficacy of its clinical treatment and also provide new possibilities for the treatment of COVID-19.

An Investigation of Pharmacokinetic Interaction of Vericiguat with Apigenin based on a Newly Developed Ultra-performance Liquid Chromatography-tandem Mass Spectrometry Assay

BACKGROUND

Vericiguat, as a new stimulator of soluble guanylate cyclase (sGC), was recently approved as a first-in-class treatment for reducing risks in patients with ejection fraction less than 45 percent and heart failure (HF) in the USA.

OBJECTIVE

The main aim of the present experiment was to establish an acceptable, sensitive assay based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for quantitatively analyzing the plasma concentration levels of vericiguat in rats, and to further evaluate the effect of apigenin on the metabolism of vericiguat in vivo.

METHOD

In sample processes, acetonitrile was finally chosen for quickly precipitating protein. The levels of vericiguat in plasma were analyzed by a Xevo TQ-S triple quadrupole tandem mass spectrometry (Milford, MA, USA) in a positive ion mode.

RESULTS

The scope of the calibration standard for vericiguat ranged from 0.5 to 1000 ng/mL, where a great linearity was acceptable. The lower limit of quantification (also called LLOQ) of vericiguat presented the sensitivity of this assay was evaluated as low as 0.5 ng/mL. Additionally, selectivity, accuracy and precision, extraction recovery, matrix effect, and stability were all verified. Subsequently, this approach also supported to assess the plasmatic concentrations of vericiguat from an interaction survey on herb-- drug, in which oral administration of apigenin (20 mg/kg) obviously increased the plasmatic levels of vericiguat and altered the pharmacokinetics of vericiguat in rats.

CONCLUSION

These results would help us to further understand the pharmacokinetic properties of vericiguat when co-administration with apigenin, and to avoid unexpected clinical risks in the future.

Bisphenol S stimulates Leydig cell proliferation but inhibits differentiation in pubertal male rats through multiple mechanisms

Bisphenol S (BPS) is a novel bisphenol A (BPA) analogue, a ubiquitous environmental pollutant that disrupts male reproductive system. Whether BPS affects Leydig cell maturation in male puberty remains unclear. Male Sprague-Dawley rats (age of 35 days) were daily gavaged to 0, 1, 10, 100, and 200 mg/kg/day from postnatal days 35-56. BPS at 1-10 mg/kg/day and higher doses markedly reduced serum testosterone and progesterone levels but it at 200 mg/kg/day significantly increased estradiol level. BPS at 100 and 200 mg/kg/day significantly elevated serum luteinizing hormone (LH) levels. BPS at 1-10 mg/kg/day and higher doses significantly reduced inhibin A and inhibin B levels. BPS at 100 and 200 mg/kg/day markedly increased CYP11A1+ Leydig cell number, but did not affect HSD11B1+ (a mature Leydig cell marker) cell number. BPS at 10 mg/kg/day and higher doses significantly downregulated the expression of Cyp11a1 and at 100 and 200 mg/kg/d significantly lowered Cyp17a1, Hsd11b1, and Nr5a1 in the testes. BPS at 100 and/or 200 mg/kg/day significantly elevated Lhb in the pituitary. BPS at 100 and 200 mg/kg/day significantly increased the phosphorylation of AKT1, AKT2, and CREB without affecting total AKT1, AKT2, and CREB levels. BPS at 1-100 μM significantly suppressed testosterone production and induced proliferation of primary immature Leydig cells after 24 h of treatment and these actions were reversed by estrogen receptor α antagonist, ICI 182780, and partially reversed by vitamin E. BPS at 0.1-10 μM significantly increased oxidative stress of Leydig cells in vitro. BPS also directly inhibited 17β-hydroxysteroid dehydrogenase 3 activity at 10-100 μM. In conclusion, BPS causes hypergonadotropic androgen deficiency in male rats during pubertal exposure via activating ESR1 and inducing ROS in immature Leydig cells and directly inhibiting 17β-hydroxysteroid dehydrogenase 3 activity.

Combination therapy using multifunctional dissolvable hyaluronic acid microneedles for oral ulcers

Oral ulcers are common in the oral mucosa. Frequent occurrences of oral ulcers commonly afflict patients, seriously impacting their daily life. Treatments with good anti-inflammatory and antibacterial properties are important for promoting the healing of oral ulcers. In this study, a multifunctional, soluble hyaluronic acid (HA) microneedle (MN) patch was prepared to promote oral ulcer healing. The tip layer of the MN patch was loaded with triamcinolone acetonide (TA) and epidermal growth factor (EGF) to inhibit inflammation and promote angiogenesis. Zeolitic imidazolate framework-8 (ZIF-8) was loaded onto the base layer of the MN patch, which effectively released Zn2+ to mediate antibacterial effects. In addition, HA exerts a protective effect on the mucous membrane. Owing to these properties, the multifunctional MN patches were found to have good anti-inflammatory, antibacterial, and tissue-healing abilities, indicating that the multifunctional MN patch design successfully promoted the healing of oral ulcers.

Effects of drug-drug interactions and CYP3A4 variants on alectinib metabolism

In this study, the effects of 17 CYP3A4 variants and drug-drug interactions (DDI) with its mechanism on alectinib metabolism were investigated. In vitro incubation systems of rat liver microsomes (RLM), human liver microsomes (HLM) and recombinant human CYP3A4 variants were established. The formers were used to screen potential drugs that inhibited alectinib metabolism and study the underlying mechanism, and the latter was used to determine the dynamic characteristics of CYP3A4 variants. Alectinib and its main metabolite M4 were quantitatively determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The results showed that compared with CYP3A4.1, only CYP3A4.29 showed higher catalytic activity, while the catalytic activity of CYP3A4.4, .7, .8, .12, .14, .16, .17, .18, .19, .20, .23, and .24 decreased significantly. Among them, the catalytic activity of CYP3A4.20 is the lowest, only 2.63% of that of CYP3A4.1. Based on the RLM incubation system in vitro, 81 drugs that may be combined with alectinib were screened, among which 18 drugs had an inhibition rate higher than 80%. In addition, nicardipine had an inhibition rate of 95.09% with a half-maximum inhibitory concentration (IC50) value of 3.54 ± 0.96 μM in RLM and 1.52 ± 0.038 μM in HLM, respectively. There was a mixture of non-competitive and anti-competitive inhibition of alectinib metabolism in both RLM and HLM. In vivo experiments of Sprague-Dawley (SD) rats, compared with the control group (30 mg/kg alectinib alone), the AUC(0-t), AUC(0-∞), Tmax and Cmax of alectinib administered in combination with 6 mg/kg nicardipine were significantly increased in the experimental group. In conclusion, the metabolism of alectinib was affected by polymorphisms of the CYP3A4 gene and nicardipine. This study provides reference data for clinical individualized administration of alectinib in the future.

Effects of dietary flavonoids on the metabolism of vortioxetine and its potential mechanism

INTRODUCTION

Quercetin and apigenin are two common dietary flavonoids widely found in foods and fruits. Quercetin and apigenin can act as the inhibitors of CYP450 enzymes, which may affect the pharmacokinetics of clinical drugs. Vortioxetine (VOR), approved for marketing by the Food and Drug Administration (FDA) in 2013, is a novel clinical drug for treating major depressive disorder (MDD).

OBJECTIVE

This study aimed to evaluate the effects of quercetin and apigenin on the metabolism of VOR in in vivo and in vitro experiments.

METHOD

Firstly, 18 Sprague-Dawley rats were randomly divided into three groups: control group (VOR), group A (VOR + 30 mg/kg quercetin) and group B (VOR + 20 mg/kg apigenin). We collected the blood samples at different time points before and after the final oral administration of 2 mg/kg VOR. Subsequently, we further used rat liver microsomes (RLMs) to investigate the half-maximal inhibitory concentration (IC50) of the metabolism of vortioxetine. Finally, we evaluated the inhibitory mechanism of two dietary flavonoids on VOR metabolism in RLMs.

RESULTS

In animal experiments, we found AUC (0-∞) (area under the curve from 0 to infinity) and CLz/F (clearance) to be obviously changed. Compared to controls, AUC (0-∞) of VOR in group A and group B was 2.22 and 3.54 times higher, respectively, while CLz/F of VOR in group A and group B was significantly decreased down to nearly two-fifth and one-third. In in vitro studies, the IC50 value of quercetin and apigenin in the metabolic rate of vortioxetine was 5.322 μM and 3.319 μM, respectively. Ki value of quercetin and apigenin was found to be 0.279 and 2.741, respectively, and the αKi value of quercetin and apigenin was 0.066 and 3.051 μM, respectively.

CONCLUSION

Quercetin and apigenin exhibited inhibitory effects on the metabolism of vortioxetine in vivo and in vitro. Moreover, quercetin and apigenin non-competitively inhibited the metabolism of VOR in RLMs. Thus, we should pay more attention to the combination between these dietary flavonoids and VOR in the future clinical use.

Effects of CYP2C19 inhibitors on mavacamten pharmacokinetics in rats based on UPLC-MS/MS

CONTEXT

CYP2C19 is an important member of the human cytochrome P450 2C (CYP2C) family. Mavacamten is a novel treatment of patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM) which was metabolized mainly by CYP2C19.

OBJECTIVE

In this study, we firstly reported and validated a quantitative analysis method of mavacamten in rat plasma based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), which was applied to the drug-drug interaction (DDI) study between mavacamten and CYP2C19 inhibitors (fluvoxamine, fluoxetine and fluconazole) in rats.

MATERIALS AND METHODS

Vericiguat was used as the internal standard (IS), and the analyte and IS were measured with electrospray ion (ESI) source in positive ion mode on a XEVO TQ-S triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode.

RESULTS

In the scope of 1.0-100 ng/mL, this assay had excellent linearity. Both intra-day and inter-day accuracy of the analyte ranged from -2.4% to 9.1%, while the precision was ≤4.2%. Matrix effect, recovery, and stability were evaluated and validated to meet the requirements for the guidelines of bioanalytical assay. When compared with the control group, AUC_0→∞ of mavacamten in fluconazole, fluoxetine and fluvoxamine were increased by 125.5%, 110.7% and 43.6%, respectively, which demonstrated that CYP2C19 inhibitors could inhibit mavacamten metabolism.

CONCLUSIONS

The results showed that CYP2C19 inhibitors could significantly improve the bioavailability of mavacamten in rats, which indicated that we should pay more attention to the patient's condition to prevent the occurrence of side effects when used mavacamten in combination with CYP2C19 inhibitors.

The effect of Resveratrol on the pharmacokinetic profile of tofacitinib and the underlying mechanism

The purpose of this study was to (i) investigate the effect of CYP3A4 variants on tofacitinib metabolism, and (ii) investigate the interaction of tofacitinib with resveratrol and its underlying mechanisms. The concentration of M9, the main metabolite of tofacitinib, was determined by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The results showed that the clearance rate of CYP3A4.18 variant was significantly decreased compared with CYP3A4.1, and the CYP3A4.28 variant was changed, but not statistically significant. In addition, the potential interaction of resveratrol with tofacitinib was determined based on rat liver microsomes (RLM), human liver microsomes (HLM), and CYP3A4 response systems. Resveratrol has an IC₅₀ of 15.67 μM in RLM with a non-competitive mechanism. In HLM with a non-competitive mechanism, the IC₅₀ value was 8.88 μM. The IC₅₀ values were 6.41 μM, 10.60 μM and 27.08 μM in CYP3A4.1, .18 and .28, respectively, all with a competitive mechanism. In the in vivo study, Sprague-Dawley (SD) rats were randomized into two groups (n = 6) to receive tofacitinib with or without resveratrol. We found that the AUC_(0-∞) of tofacitinib in the experimental group increased to around 207.5% compared with the control group. And C_max increased to 260.0%. In summary, our data showed that resveratrol significantly affect the metabolism of tofacitinib, thus providing basic data for the precise clinical application of tofacitinib.

Effect of flavonoids and CYP3A4 variants on midostaurin metabolism

The objective of this study was to determine the effect of flavonoids on midostaurin disposition considering co-administration and metabolic enzyme gene polymorphism. Enzymatic incubation assays were performed in vitro, while in vivo experiments were conducted in Sprague-Dawley rats. The analytes were determined via UPLC-MS/MS. We found that myricetin was the most potent among the investigated 10 flavonoids in suppressing the metabolism of midostaurin, with an IC₅₀ at a low μM level. After co-administration of midostaurin and myricetin, the plasma concentration of midostaurin's primary metabolite CGP62221 was reduced corresponding to myricetin exposure. Furthermore, CYP3A4 homologous rat protein CYP3A2 was reduced significantly in the co-administration group. Thereafter, the kinetic parameters of 23 recombinant human CYP3A4 variants were determined using midostaurin. The relative intrinsic clearance varied from 269.63% in CYP3A4.29-8.95% in CYP3A4.17. In addition, the inhibitory potency of myricetin was substantially different for CYP3A4.29 and CYP3A4.17 compared with wild type, with IC₅₀ values of 9.85 ± 0.27 μM and 90.99 ± 16.13 μM, respectively. Collectively, our data demonstrated that flavonoids, particularly myricetin, can inhibit the metabolism of midostaurin. Additionally, CYP3A4 genetic polymorphism may contribute to stratification of midostaurin blood exposure.

Case Report of Neonatal Sotos Syndrome with a New Missense Mutation in the NSD1 Gene and Literature Analysis in the Chinese Han Population

Currently, no consensus exists regarding Sotos syndrome in the Chinese population. Here, we present a case of neonatal Sotos syndrome, followed by a retrospective analysis of five cases of neonatal Sotos syndrome, reported in China. The study subject was a twin premature infant, heavier than gestational age, with characteristic facial features, limb shaking, and hypertonia. Transient hypoglycemia, abnormal cranial magnetic resonance imaging, multiple nodules in polycystic kidneys and liver, abnormal hearing, patent ductus arteriosus, and an atrial septal defect were also noted. The subject showed overgrowth and developmental retardation at 3 months of age. Sequencing revealed a novel missense mutation, c.5000C>A, in the nuclear receptor binding the SET domain protein 1 gene, resulting in an alanine-to-glutamate substitution. The bioinformatics analysis suggested high pathogenicity at this site. This study provides insights into diagnosis of neonatal Sotos syndrome based on specific phenotypes. Subsequent treatment and follow-up should focus on developmental retardation, epilepsy, and scoliosis.

Inhibition of Axitinib on Buspirone Metabolism in vitro and in vivo

Objective

To evaluate the effect of axitinib on buspirone metabolism in vitro and in vivo.

Methods

A microsome incubation assay was performed to study the effect and mechanism of axitinib on buspirone metabolizing. In vivo, buspirone was administered with or without axitinib to Sprague–Dawley rats. Plasma samples were collected and subjected to ultra-performance liquid chromatography–tandem mass spectrometry.

Results

In both human liver microsomes (HLMs) and rat liver microsomes (RLMs), axitinib (100 μM) decreased buspirone hydroxylation and N-dealkylation by >85%. Axitinib inhibited buspirone hydroxylation and N-dealkylation, with an IC₅₀ of 15.76 and 9.74 for RLMs, and 10.63 and 9.902 for HLMs. Axitinib showed noncompetitive inhibition of both 6′-hydroxylation and N-dealkylation. Moreover, coadministration of axitinib and buspirone led to an increase in the maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) of buspirone by 4.3- and 5.3-fold, respectively, compared with the control group.

Conclusion

Axitinib inhibited buspirone metabolism in vivo and in vitro, which increases the risk of the side effects of buspirone in the clinic. When coadministered with axitinib, a lower dosage of buspirone should be defined to avoid a toxic response. Axitinib is suspected to function as an inhibitor of CYP3A4.

Effect of Baicalein on the Pharmacokinetics of Cilostazol and Its Two Metabolites in Rat Plasma Using UPLC-MS/MS Method

This study aimed to explore the effect of baicalein on the pharmacokinetics of cilostazol (CLZ) and its two metabolites 3,4-dehydro cilostazol (3,4-CLZ) and 4'-trans-hydroxy cilostazol (4'-CLZ) in rats using a newly established ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method. Ticagrelor was used as an internal standard (IS), then cilostazol and its two metabolites were separated by means of a UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) using gradient elution method with 0.4 ml/min of flow rate. Acetonitrile as organic phase and water with 0.1% formic acid as aqueous phase constructed the mobile phase. Selective reaction monitoring (SRM) mode and positive ion mode were preferentially chosen to detect the analytes. Twelve SD rats were divided into two groups (n = 6) when CLZ was administered orally (10 mg/kg) with or without oral baicalein (80 mg/kg). The selectivity, linearity, recovery, accuracy, precision, matrix effect and stability of UPLC-MS/MS assay were satisfied with the standards of United States Food and Drug Administration guidelines. In control group, AUC_0-∞ and C_max of CLZ were 2,169.5 ± 363.1 ng/ml^*h and 258.9 ± 82.6 ng/ml, respectively. The corresponding results were 3,767.6 ± 1,049.8 ng/ml^*h and 308.6 ± 87.9 ng/ml for 3, 4-CLZ, 728.8 ± 189.9 ng/ml^*h and 100.3 ± 51.3 ng/ml for 4'-CLZ, respectively. After combination with baicalein, AUC_0-∞ and C_max of CLZ were 1.48, 1.38 times higher than the controls. Additionally, AUC_0-∞ and C_max were separately decreased by 36.12 and 19.54% for 3,4-CLZ, 13.11 and 44.37% for 4'-CLZ. Baicalein obviously alters the pharmacokinetic parameters of CLZ, 3,4-CLZ and 4'-CLZ in rats. These results suggested that there was a potential drug-drug interaction between baicalein and CLZ. Therefore, it must raise the awareness when concomitant use of CLZ with baicalein, the dosage regimen of CLZ should be taken into consideration, if this result is confirmed in clinical studies.

Characterization of Alpelisib in Rat Plasma by a Newly Developed UPLC-MS/MS Method: Application to a Drug-Drug Interaction Study

Alpelisib, an oral selective and small-molecule phosphoinositide 3-kinase inhibitor, was lately approved in the United States to treat breast cancer. A sensitive method to quantify alpelisib levels in rat plasma on the basis of ultra-performance liquid chromatography–tandem mass spectrometry technique was established and validated, which was successfully employed to explore the effects of CYP3A4 inhibitors on alpelisib pharmacokinetics in rats. A C18 column named Acquity UPLC BEH C18 was applied to achieve the separation of alpelisib and internal standard duvelisib after protein precipitation with acetonitrile. The mobile phase in this study had two components, namely, acetonitrile and water having 0.1% formic acid, and a program with gradient elution method was used at a flow rate of 0.40 ml/min. Mass spectrometry in a positive multiple reaction monitoring mode was operated. In the scope of 1–5,000 ng/ml, this assay had excellent linearity. Our newly developed assay was verified in all aspects of bioanalytical method validation, involving lower limit of quantification, selectivity, accuracy and precision, calibration curve, extraction recovery, matrix effect, and stability. Then, this assay was used to detect the plasma levels of alpelisib from a drug-drug interaction investigation, where ketoconazole remarkably increased the plasma concentration of alpelisib and changed alpelisib pharmacokinetics more than itraconazole. This study will help better understand the pharmacokinetic properties of alpelisib, and further clinical studies should be done to confirm this result in patients.

Effects of 31 recombinant CYP2C19 variants on clomipramine metabolism in vitro

BACKGROUND

CYP2C19 is an important member of the cytochrome P450 enzyme superfamily. We recently identified 31CYP2C19 alleles in the Han Chinese population; studying the effects of CYP2C19 on drug metabolism can help reduce adverse drug reactions and therapeutic failure.

AIM

The aim of this study was to assess the catalytic activities of 31 allelic isoforms and their effects on the metabolism of clomipramine in vitro.

METHODS

The wild-type and 30 CYP2C19 variants were expressed in insect cells, and each variant was characterized using clomipramine as the substrate. Reactions were performed at 37°C with 5-150 μmol/L substrate for 30 min. By using ultra-high-performance liquid chromatography-mass spectrometry to detect the products, the kinetic parameters Km, Vmax, and intrinsic clearance (Vmax/Km) of N-desmethyl clomipramine were determined.

RESULTS

Among the CYP2C19 variants tested, CYP2C19*29, L16F, and T130M showed extremely increased intrinsic clearance of clomipramine, CYP2C19*3C, and N277K showed similar intrinsic clearance (Vmax/Km) values with CYP2C19*1, while the intrinsic clearance values of other variants were significantly decreased (from 0.65% to 63.28%). In addition, CYP2C19*3 and 35FS could not be detected because they have no detectable enzyme activity.

CONCLUSIONS

As the first report of 31 CYP2C19 alleles for clomipramine metabolism, our study could provide corresponding reference for clomipramine for further studies in vivo and offer valuable information relevant to the personalized medicine for CYP2C19-metabolized drug.

TA allele of rs2070673 in the CYP2E1 gene is associated with lobular inflammation and nonalcoholic steatohepatitis in patients with biopsy-proven nonalcoholic fatty liver disease

BACKGROUND AND AIM

Cytochrome P450 2E1 (CYP2E1) plays a role in lipid metabolism, and by increasing hepatic oxidative stress and inflammation, the upregulation of CYP2E1 is involved in development of nonalcoholic steatohepatitis (NASH). We aimed to explore the relationship between CYP2E1-333A>T (rs2070673) and the histological severity of nonalcoholic fatty liver disease (NAFLD).

METHODS

We studied 438 patients with biopsy-proven NAFLD. NASH was defined as NAFLD Activity Score ≥ 5 with existence of steatosis, ballooning, and lobular inflammation. CYP2E1-333A>T (rs2070673) was genotyped by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Serum cytokines related to inflammation were measured by the Bio-plex 200 system to investigate possible mediating factors involved in the process.

RESULTS

The TA genotype of rs2070673 had a higher prevalence of moderate/severe lobular inflammation (27.6% vs 20.3% vs 13.3%, P < 0.01) and NASH (55.7% vs 42.4% vs 40.5%, P < 0.01) compared with the AA and TT genotypes, respectively. In multivariable regression modeling, the heterozygote state TA was associated with moderate/severe lobular inflammation (adjusted odds ratio: 2.31, 95% confidence interval 1.41-3.78, P < 0.01) or NASH (adjusted odds ratio: 1.82, 95% confidence interval 1.22-2.69, P < 0.01), independently of age, sex, common metabolic risk factors, and presence of liver fibrosis. Compared with no-NASH, NASH patients had significantly higher levels of serum interleukin-1 receptor antagonist, interleukin-18, and interferon-inducible protein-10 (IP-10), whereas only IP-10 was increased with the rs2070673 TA variant (P = 0.01). Mediation analysis showed that IP-10 was responsible for ~60% of the association between the rs2070672 and NASH.

CONCLUSIONS

The TA allele of rs2070673 is strongly associated with lobular inflammation and NASH, and this effect appears to be largely mediated by serum IP-10 levels.

Development of a Prognostic Five-Gene Signature for Diffuse Lower-Grade Glioma Patients

Background: Diffuse lower-grade gliomas (LGGs) are infiltrative and heterogeneous neoplasms. Gene signature including multiple protein-coding genes (PCGs) is widely used as a tumor marker. This study aimed to construct a multi-PCG signature to predict survival for LGG patients.

Methods: LGG data including PCG expression profiles and clinical information were downloaded from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA). Survival analysis, receiver operating characteristic (ROC) analysis, and random survival forest algorithm (RSFVH) were used to identify the prognostic PCG signature.

Results: From the training (n = 524) and test (n = 431) datasets, a five-PCG signature which can classify LGG patients into low- or high-risk group with a significantly different overall survival (log rank P < 0.001) was screened out and validated. In terms of prognosis predictive performance, the five-PCG signature is stronger than other clinical variables and IDH mutation status. Moreover, the five-PCG signature could further divide radiotherapy patients into two different risk groups. GO and KEGG analysis found that PCGs in the prognostic five-PCG signature were mainly enriched in cell cycle, apoptosis, DNA replication pathways.

Conclusions: The new five-PCG signature is a reliable prognostic marker for LGG patients and has a good prospect in clinical application.

A Novel UPLC-MS/MS Assay for the Measurement of Linezolid and its Metabolite PNU-142300 in Human Serum and its Application to Patients With Renal Insufficiency

The contribution of the metabolites of linezolid to the associated myelosuppression is unknown in patients who are renal impairment. In this research, the purpose of our experiment was to explore and develop a quick and robust ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay for the determination of linezolid and its metabolite PNU-142300 in human serum simultaneously. The analytes were prepared using a simple and convenient approach with acetonitrile for protein crash, and then separated from the matrix on a Waters Acquity Ultra performance liquid chromatography (UPLC) BEH C18 (2.1 mm × 50 mm, 1.7 μm) column in a program of gradient elution, where the mobile phase was consisted of water with 0.1% formic acid and acetonitrile, and was placed at 0.40 ml/min flow rate. Multiple reaction monitoring (MRM) was employed and conducted for UPLC-MS/MS detection with ion transitions at m/z 338.01 → 296.03 for linezolid, m/z 369.96 → 327.98 for PNU-142300 and m/z 370.98 → 342.99 for tedizolid (Internal standard, IS), respectively. This method had good linearity respectively in the calibration range of 0.01–20 μg/ml for linezolid, and 0.05–100 μg/ml for PNU-142300. In the intra- and inter-day, the precision of linezolid and PNU-142300 was below 14.2%, and the accuracy in this method was determined to be from −9.7 to 12.8%. In addition, recovery and matrix effect of the analytes were all found to be acceptable, and the analytes during the assay and storage in serum samples were observed to be stable. The novel optimized UPLC-MS/MS assay was also successfully employed to determine the concentration levels of linezolid and PNU-142300 in human serum. The results showed that linezolid-associated myelosuppression occurs more frequently in patients with renal insufficiency, and the metabolite-to-parent concentration ratio of PNU-142300 is predicted to reduce this toxicity of myelosuppression.

Effects of 27 CYP3A4 protein variants on saxagliptin metabolism in vitro

Saxagliptin is a dipeptidyl peptidase 4 (DPP-4) inhibitor widely used in patients with type 2 diabetes. It can increase the amount of insulin after meals and lower blood sugar. CYP450 3A4 (CYP3A4) can metabolize about 30%-40% of therapeutic drugs. Individual differences caused by CYP3A4 genetic polymorphisms can lead to treatment failure, unpredictable side effects, or severe drug toxicity. The aim of this study was to evaluate the catalytic activities of 27 CYP3A4 variants on saxagliptin metabolism in vitro, which were identified in human CYP alleles. We successfully constructed 27 kinds of wild-type and variant vectors of pFast-dual-OR-3A4 by overlap extension PCR and prepared 27 kinds of CYP3A4 highly expressed cell microsomes by baculovirus insect cell expression system. The ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was used to detect the concentrations of the metabolite of saxagliptin (5-hydroxysaxagliptin) and the internal standard. Compared with the wild-type CYP3A4.1, the intrinsic clearance values of most varieties decreased to 1.91%-77.08%. Most of these varieties showed a decrease in V_max and an increase in Km values compared with wild type. We are the first to report the vitro metabolic data of 27 CYP3A4 variants of the metabolism of saxagliptin which can deepen our understanding of individualized drug use by combining previous studies about the effects of CYP3A4 variants of drug metabolism. With further in vivo studies, we hope it can guide individualized drug use in the clinic when the variants with low metabolic activity to saxagliptin were sequenced in the human body.

Identification and Enzymatic Activity Evaluation of a Novel CYP2C9 Allelic Variant Discovered in a Patient

Warfarin is a widely prescribed anticoagulant but the doses required to attain the optimum therapeutic effect exhibit dramatic inter-individual variability. Pharmacogenomics-guided warfarin dosing has been recommended to improve safety and effectiveness. We analyzed the cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) genes among 120 patients taking warfarin. A new coding variant was identified by sequencing CYP2C9. The novel A > G mutation at nucleotide position 14,277 led to an amino acid substitution of isoleucine with valine at position 213 (I213V). The functional consequence of the variant was subsequently evaluated in vitro. cDNA of the novel variant was constructed by site-directed mutagenesis and the recombinant protein was expressed in vitro using a baculovirus–insect cell expression system. The recombinant protein expression was quantified at apoprotein and holoprotein levels. Its enzymatic activities toward tolbutamide, warfarin and losartan were then assessed. It exhibited changed apparent Km values and increases of 148%, 84% and 67% in the intrinsic clearance of tolbutamide, warfarin and losartan, respectively, compared to wild-type CYP2C9*1, indicating dramatically enhanced in vitro enzymatic activity. Our study suggests that the amino acid at position 213 in wild-type CYP2C9*1 may be important for the enzymatic activity of CYP2C9 toward tolbutamide, warfarin and losartan. In summary, a patient taking high-dose warfarin (6.0 mg/day) in order to achieve the target international normalized ratio was found to have a mutation in the CYP2C9 gene.

In vivo Pharmacokinetic Drug-Drug Interaction Studies Between Fedratinib and Antifungal Agents Based on a Newly Developed and Validated UPLC/MS-MS Method

In the current research experiment, a sensitive, precise and rapid bioanalytical approach involving the detection of fedratinib concentrations in rat plasma by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) technique was optimized and established, and it was employed to describe the changes of fedratinib concentrations after oral treatment with various antifungal drugs (isavuconazole, posaconazole, fluconazole and itraconazole). An Acquity UPLC BEH reverse-phase C18 column (2.1 mm × 50 mm, 1.7 μm) was used for chromatographic separation of fedratinib and bosutinib (as internal standard (IS) in our study) under a linear gradient elution of the mobile phase, which was composed of solution A (acetonitrile) and solution B (water with 0.1% formic acid), along with 0.40 ml/min flow rate. The analyte and internal standard were measured with electrospray ion source in positive ion mode on a XEVO TQS triple quadrupole tandem mass spectrometer. The newly developed UPLC-MS/MS assay displayed enough linearity within the concentration range of 0.5–500 ng/ml for calibration curve. The intra- and inter-day of precision and accuracy were evaluated and validated to meet the requirements for the guidelines of bioanalytical assay. In addition, the findings of matrix effect, recovery, and stability were all within the acceptable limits. The new UPLC-MS/MS method was also successfully applied to characterize the pharmacokinetic changes of fedratinib in rats in the present of different antifungal drugs (such as isavuconazole, posaconazole, fluconazole and itraconazole). It turned out that fluconazole resulted in a prominent inhibitory effect on fedratinib metabolism in rats, followed by treatment with itraconazole and isavuconazole. Therefore, the toxicity of fedratinib should be avoided when the concurrent use of fedratinib with CYP3A4 inhibitors may occur.

Determination and Pharmacokinetic Profiles of Four Active Components From Scrophularia ningpoensis Hemsl. in Rats

Acteoside, angoroside C, harpagoside, and cinnamic acid, which are the main bioactive ingredients of Scrophularia ningpoensis Hemsl., have wide clinical use with various biological effects. A new and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established with taxifolin as the internal standard (IS) in this study and was successfully used to study the pharmacokinetic profiles of four active components from S. ningpoensis Hemsl. in rats after sublingual intravenous administration. After protein precipitation with acetonitrile, the mobile phase (consisting of acetonitrile and 0.1% formic acid) was used to separate the analytes on an Acquity UPLC BEH C18 chromatography column (2.1 × 50 mm, 1.7 μm) under gradient elution. The precursor-to-product ion transitions of 623.4 → 161.3 m/z for acteoside, 783.5 → 175.0 m/z for angoroside C, 493.3 → 345.2 m/z for harpagoside and 147.2 → 103.4 m/z for cinnamic acid were monitored by mass spectrometry with negative electrospray ionization in the multiple reaction monitoring (MRM) mode. The concentration range of 10–1,000 ng/ml could be detected by this method with a lower limit of quantification (LLOQ) of 10 ng/ml for each analyte. The intra- and inter-day precision (RSD%) of the method ranged from 2.6 to 9.9% and 2.7–11.5%, respectively. Meanwhile, the accuracy (RE%) was −9.6–10.7% in this developed method. The mean recoveries of four active components from S. ningpoensis Hemsl. were more than 76.7% with negligible matrix effects. The four active components from S. ningpoensis Hemsl. were stable under multiple storage and process conditions. A new, sensitive and simple analytical method had been established and was successfully applied to the pharmacokinetic profiles of four active components from S. ningpoensis Hemsl. in rats after sublingual intravenous administration.

Inhibitory effect of sesamin on ivabradine metabolism in rats

In this work, the aim of our study was to assess whether sesamin could influence the pharmacokinetics of ivabradine and its active metabolite N-desmethylivabradine in rats. At the begining, 12 healthy male Sprague-Dawley rats were randomly divided into two groups: The rats were received an oral administration of 1.0mg/kg ivabradine alone (the control group), and the rats were given 1.0mg/kg ivabradine co-administered with 50mg/kg sesamin by gavage (the test group). After that, blood samples were collected from the tail vein of rats, and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) were used for determing the plasma concentrations of ivabradine and N-desmethylivabradine in rats. Finally, the pharmacokinetic parameters were estimated using DAS 2.0 software. As the results, the pharmacokinetic parameters (t_1/2, C_max, AUC _(0-t) and AUC _(0-oo)) of ivabradine in the control group were significantly lower than those in the test group (P<0.05). Moreover, sesamin significantly decreased t_1/2, C_max, AUC_(0-t) and AUC_(0-oo) of N-desmethylivabradine when compared to the control. These results demonstrated that sesamin increases plasma concentration of ivabradine and decreases N-desmethylivabradine conversely. Hence, our data indicated sesamin could influence the pharmacokinetic profile of ivabradine in rats, which might cause food-drug interaction in humans.

Simultaneous quantification and pharmacokinetic investigation of selexipag and its main metabolite ACT-333679 in rat plasma by UPLC-MS/MS method

In the present study, an accurate, simple and fast bioanalytical method based on ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) technique for simultaneous quantification of plasma selexipag and its main metabolite ACT-333679 concentrations in rats was optimized and established. The purpose of chromatographic separation of selexipag, ACT-333679 and the internal standard (IS, diazepam) was accomplished using an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 μm) column. The mobile phase was consisted of acetonitrile (solution A) and 0.1 % formic acid in water (solution B) in a linear gradient elution procedure with a flow rate of 0.40 mL/min. The measurement of the analytes and IS was explored using a XEVO TQ-S triple quadrupole tandem mass spectrometer, which was comprised with electrospray ionization (ESI) source in positive ion mode. Selected multiple reaction monitoring (MRM) mode was employed to detect the parent-to-daughter ion transitions as follows: m/z 497.4 → 302.2 for selexipag, m/z 420.1 → 378.2 for ACT-333679, and m/z 285.0 → 154.0 for diazepam (IS), respectively. The new UPLC-MS/MS method showed good linearity respectively at the calibration curve range of 0.05-50 ng/mL for selexipag, and 0.05-250 ng/mL for ACT-333679. The intra- and inter-day of accuracy and precision were all within the acceptable limits in the bioanalytical method, and the results of recovery and matrix effect were also met the requirements. The newly developed UPLC-MS/MS assay was forward successfully used to describe the pharmacokinetic profiles of selexipag and ACT-333679 in rats after oral treatment with 6.0 mg/kg selexipag.

Development of a novel and quick UPLC-MS/MS method for the pharmacokinetic analysis of duvelisib in beagle dogs

Duvelisib, a new oral phosphoinositide-3-kinase (PI3K)-δ and PI3K-γ inhibitor, was recently approved in the USA as the therapeutic drug for patients with the diseases of relapsed or refractory chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). In the present study of our research, a quick and simple bioanalytical method based on ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) technique was fully explored and established for the quantification of plasma duvelisib concentrations from beagle dog in which gilteritinib was used as the internal standard (IS). After a simple and quick protein precipitation treated with acetonitrile, the chromatographic separation of the analyte was carried out on an Acquity BEH C18 column (2.1 mm × 50 mm, 1.7 μm) conducted in a gradient elution procedure where acetonitrile (solvent A) and 0.1 % formic acid in water (solvent B) consisted as the mobile phase. The measurements of the analyte and IS were explored using a XEVO TQS triple quadrupole tandem mass spectrometer, which was comprised with electrospray ionization (ESI) source in positive ion mode. Selected reaction monitoring (SRM) mode was employed to detect the parent-to-daughter ion transitions as follows: m/z 416.88 → 281.88 for duvelisib, and m/z 553.09 → 436.01 for IS, respectively. The assay was successfully established in the calibration range from 0.5 to 3000 ng/mL for duvelisib, where the lower limit of quantification (LLOQ) was set at 0.5 ng/mL. The precisions of intra-day and inter-day for duvelisib were all below 12.6 %, and the accuracies were from -2.5% to 14.1%. Both matrix effect and mean recovery of the analyte and IS were all acceptable, and the analyte was stable during the assay and storage in dog plasma samples. The novel established bioanalytical method based on UPLC-MS/MS technique was effectively employed to the investigation of the pharmacokinetic profile of duvelisib in beagle dogs following a 1.34 mg/kg single dose of oral administration.

Inhibitory effects of voriconazole, itraconazole and fluconazole on the pharmacokinetic profiles of ivosidenib in rats by UHPLC-MS/MS

Ivosidenib, as an oral mutant isocitrate dehydrogenase 1 (mIDH1) inhibitor, was awarded approval in the USA for the targeted therapy of relapsed or refractory acute myeloid leukemia (AML) in adult patients, who also had a susceptible enzyme to mIDH1. The aim of our present study was to develop and validate an accurate and fast assay based on the ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) technique for the quantification of ivosidenib in plasma and to investigate the possible effects of different CYP3A4 inhibitors (voriconazole, itraconazole and fluconazole) on ivosidenib metabolism in rats. After the fast protein crash with acetonitrile, chromatographic separation of ivosidenib and erlotinib (used as the internal standard in this experiment, IS) was accomplished using an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 μm) column, and detection of the analyte was also performed using a Xevo TQ-S triple quadrupole tandem mass spectrometer in the positive ion electrospray ionization (ESI) interface. The assay showed enough linearity over a 0.5-6000 ng/mL calibration range. The application of the validated bioanalytical method based on the UHPLC-MS/MS technique was further successfully exhibited in an animal study of the drug-drug interaction between ivosidenib (50 mg/kg) and voriconazole (20 mg/kg)/itraconazole (20 mg/kg)/fluconazole (20 mg/kg) in rats. Voriconazole, itraconazole and fluconazole increased the exposure of ivosidenib in plasma by different degrees and also had a potential inhibitory effect on the metabolism of ivosidenib. Thus, a dose reduction or interruption of ivosidenib may be important to guide the practice of clinical medicine.

Functional characteristics of CYP3A4 allelic variants on the metabolism of loperamide in vitro

Background

Cytochrome P450 3A4 (CYP3A4) appears to be genetically polymorphic, which in turn contributes to interindividual variability in response to therapeutic drugs. Loperamide, identified as a CYP3A4 substrate, is prone to misuse and abuse and has high risks of life-threatening cardiotoxicity.

Methods

Thus, this study is designed to evaluate the enzymatic characteristics of 29 CYP3A4 alleles toward loperamide in vitro, including the 7 novel CYP3A4 variants (*28-*34). The incubation system (containing CYP3A4 enzyme, cytochrome b5, 0.5-20 μM loperamide, potassium phosphate buffer and nicotinamide adenine dinucleotide phosphate) was subject to 40-mins incubation at 37°C and the concentrations of N-demethylated loperamide were quantified by UPLC-MS/MS.

Results

As a result, CYP3A4.6, .17, .20 and .30 showed extremely low activity or no activity and the rest of CYP3A4 variants presented varying degrees of decrements in catalytical activities when compared with CYP3A4.1.

Conclusion

As the first study to identify the properties of these CYP3A4 variants toward loperamide metabolism, our investigation may establish the genotype-phenotype relationship for loperamide, predict an individual's capability in response to loperamide, and provide some guidance of clinical medication and treatment for loperamide.

Characterization of Genetic Variation in CYP3A4 on the Metabolism of Cabozantinib in Vitro

Cabozantinib is a multityrosine kinase inhibitor and has a wide range of applications in the clinic, whose metabolism is predominately dependent on CYP3A4. This study was performed to characterize the enzymatic properties of 29 CYP3A4 alleles toward cabozantinib and the functional changes of five selected alleles (the wild-type, CYP3A4.2.8.14 and .15) toward cabozantinib in the presence of ketoconazole. Cabozantinib, 1-100 μM, with/without the presence of ketoconazole and CYP3A4 enzymes in the incubation system went through 30 min incubation at 37 °C, and the concentrations of cabozantinib N-oxide were quantified by UPLC-MS/MS to calculate the corresponding kinetic parameters of each variant. Collectively, without the presence of ketoconazole, most variants displayed defective enzymatic activities in different degrees, and only CYP3A4.14 and .15 showed significantly augmented enzymatic activities. With the presence of ketoconazole, five tested CYP3A4 alleles, even CYP3A4.14 and .15, exhibited obvious reductions in intrinsic clearance. Besides, we compared cabozantinib with regorafenib in relative clearance to confirm that CYP3A4 has the property of substrate specificity. As the first study of CYP3A4 genetic polymorphisms toward cabozantinib, our observations can provide prediction of an individual's capability in response to cabozantinib and guidance for medication and treatment of cabozantinib.

Drug-drug interaction study of imatinib and voriconazole in vitro and in vivo

Background: In clinical practice, common problem polypharmacy could result in the increased risks of drug-drug interactions (DDIs). Co-administered imatinib (IMA) and voriconazole (VOR) as one treatment protocol in cancer patients with fungal infections are common.Purpose: The aim of the present study was to assess the potential DDIs associated with the concurrent use of IMA and VOR in rat liver microsomes (RLMs) and in rats.Methods and results: The concentration levels of IMA, VOR, and their metabolites N-desmethyl IMA (CGP74588) and N-oxide voriconazole (N-oxide VOR) were determined by ultra performance liquid chromatography-tandem mass spectrometry. In vitro study of RLMs, VOR inhibited the IMA metabolism with the half-maximal inhibitory concentration (IC₅₀) of 105.20 μM, while IC₅₀ for IMA against VOR was 61.30 μM. After co-administered IMA and VOR in rats, the C _max of IMA was increased significantly, while the AUC_0→t, AUC_0→∞, and C _max of CGP74588 were decreased significantly. In addition, similar results were also found that the main pharmacokinetic parameters (AUC_0→t, AUC_0→∞, MRT_0→∞, T _max, and C _max) of VOR were increased significantly, while the AUC_0→t, AUC_0→∞, and C _max of N-oxide VOR were decreased significantly. Incorporation of all the results indicated that both drugs had a inhibitory effect on each other's metabolism in vitro and in vivo.Conclusion: Thus, it is of great value to monitor the concomitant use of IMA and VOR in the clinic to reduce the risks of unexpected clinical outcomes.

Simvastatin prevents and ameliorates depressive behaviors via neuroinflammatory regulation in mice

BACKGROUND

Statins play a beneficial role in the treatment of coronary artery disease and are widely prescribed to prevent hypercholesterolemia. Previous studies have demonstrated that statins also have anti-inflammatory and immunomodulatory properties, and these are being explored for potential benefits in depression. However, the role of statins in the treatment of depression has not been well examined.

METHODS

We investigated the effects of simvastatin on depressive behaviors and neuroinflammation in lipopolysaccharide (LPS) and chronic mild stress (CMS) induced depression model in mice. Sucrose preference test (SPT), forced swimming test (FST), novelty-suppressed feeding test (NSFT) were used to detect the depressive behaviors. The microglial activation was detected by immunohistochemistry analysis and the pro-inflammatory cytokines expressions including IL-1β, TNF-α and IL-6 were examined by Western blot analysis.

RESULTS

Our data indicated that oral administration of simvastatin at 20 mg/kg significantly prevented and ameliorated depressive behaviors reflected by better performance in the SPT, FST and NSFT. Moreover, simvastatin markedly prevented and ameliorated LPS and CMS-induced neuroinflammation, as shown by the suppressed activation of microglia in hippocampus and decreased hippocampal pro-inflammatory cytokines expressions including IL-1β, TNF-α, IL-6, which might be mediated via the inhibition of NF-κB pathway, as shown by the decreased nuclear NF-κB p65 expression.

LIMITATIONS

The interpretation of the evidence of a positive treatment effect of simvastatin on the depressive manifestations, multifaceted etiology of depression, and confirmation of this finding from animal models to humans is needed.

CONCLUSION

These results suggest that simvastatin has the potential to be employed as a therapy for depression associated with neuroinflammation.

UPLC-MS/MS method for the simultaneous determination of imatinib, voriconazole and their metabolites concentrations in rat plasma

In the present study, a simple ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method used to measure the plasma concentrations of imatinib, voriconazole and their metabolites (N-desmethyl imatinib and N-oxide voriconazole) in rats simultaneously making use of diazepam as the internal standard (IS) had been developed and validated. A simple protein precipitation by acetonitrile was employed for the sample preparation, then the analytes (imatinib, voriconazole and their metabolites) were eluted on an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) using the mobile phase that made up by acetonitrile (A) and 0.1% formic acid in water (B). In positive ion mode, four analytes and IS were monitored by multiple reaction monitoring (MRM) as the following mass transition pairs: m/z 494.3→394.2 for imatinib, m/z 480.3→394.2 for N-desmethyl imatinib, m/z 350.1→281.1 for voriconazole, m/z 366.1→224.1 for N-oxide voriconazole, and m/z 285.0→154.0 for IS. This method exhibited a good linearity for each analyte. Inter-day and intra-day precision were determined with values of 0.3-14.8% and 2.6-14.8%, respectively; the accuracy values were from -12.5% to 10.2%. Finally, data of matrix effect, extraction recovery, and stability were all conformed to the bioanalytical method validation of acceptance criteria of FDA recommendations. This method is an efficient tool for simultaneous determination of the four analytes and has been successfully applied for pharmacokinetic study in rats.

UPLC-MS/MS method for the quantification of ertugliflozin and sitagliptin in rat plasma

In the present study, an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) approach was designed to concurrently measure the levels of ertugliflozin and sitagliptin in rat plasma with diazepam as the internal standard (IS). Acetonitrile-based protein precipitation was applied for sample preparation, then analytes (ertugliflozin and sitagliptin) were subjected to gradient elution chromatography with a mobile phase composed of acetonitrile (A) and 0.1% formic acid in water (B). Ertugliflozin was monitored by m/z 437.2 → 329.0 transition for quantification and m/z 437.2 → 207.5 transition for qualification, and sitagliptin was determined by m/z 408.2 → 235.0 transition for quantification and m/z 408.2 → 174.0 transition for qualification by multiple reaction monitoring (MRM) in positive ion electrospray ionization (ESI) source. When the concentration of ertugliflozin ranged from 1 to 1000 ng/mL and sitagliptin ranged from 2 to 2500 ng/mL, the method exhibited good linearity. For both ertugliflozin and sitagliptin, the intra- and inter-day precision were determined with the values of 1.6-10.9% and 0.8-13.3%, respectively; and the accuracy ranged from -5.7% to 14.6%. Matrix effect, extraction recovery, and stability data were in line with the stipulated FDA guidelines for validating a bioanalytical method. The validity of the designed method was confirmed through the pharmacokinetic experiments.

The effects of cytochrome P450 2C19 polymorphism on the metabolism of voriconazole in vitro

Background

CYP/CYP450 2C19 (CYP2C19) is a highly polymorphic enzyme and exhibits individual differences in metabolic activity. The purpose of this research was mainly to explore the catalytic activities of 30 CYP2C19 variants on the substrate voriconazole in vitro, including 24 novel CYP2C19 variants (2C19.2E-.2H, .2J, .3C, .29-.33, L16F, 35FS, R124Q, R125G, T130M, N231T, M255T, R261W, N277K, S303N, I327T, N403I, and A430V) found in Chinese Han population for the first time.

Methods

These CYP2C19 variants were expressed in Spodoptera frugiperda (Sf) 21 insect cells using the baculovirus-mediated expression system. The substrate voriconazole was incubated with the abovementioned proteins at 37°C for 30 minutes in an appropriate designed system. Then through detecting its major metabolite voriconazole N-oxide by ultra-performance liquid chromatography tandem mass spectrometry, available data were obtained to explain the influence of CYP2C19 polymorphisms on voriconazole.

Results

From the results, when compared to CYP2C19.1, most variants exhibited either reduced V_max and/or increased K_m value, indicating that the intrinsic clearance (V_max/K_m) values of most variants were significantly altered. The catalytic activities of 20 novel variants exhibited decreases in different degrees compared to CYP2C19.1, with relative clearance values ranging from 1.11% to 83.78%. However, L16F exhibited the increased catalytic activity for 135.68%. In addition, the kinetic parameters of four variants (2C19.2H, .3, 35FS, and R124Q) could not be detected, due to the defective gene.

Conclusion

This is the first study to report the effects of CYP2C19 polymorphisms on vori-conazole metabolism in vitro, and we hope these data could lay the foundation for the early clinical research and individualized treatment.

The changes of expressive levels of IL-17A, STAT3, and RORγt in different invasive pulmonary aspergillosis mice

Background

T helper 17 (Th17) lymphocytes play an important role in Aspergillus adaptive immune response against Aspergillus fumigatus, but there is little attention focused on the different types of immunosuppressive models in which invasive pulmonary aspergillosis (IPA) develops. In addition, the expression levels of signal transducer and activator of transcription 3 (STAT3)/retinoic acid-related orphan nuclear receptor gamma (RORγt)/interleukin (IL)-17A signaling pathway, which is involved in the regulation of Th17 cells, as well as whether there are differences between two types of IPA mice models, remain unknown.

Materials and methods

Six to eight weeks old female BALB/c mice were treated with cortisone acetate or cyclophosphamide to establish the immunosuppressive mice models, and then, A. fumigatus inoculum was injected to form the IPA groups and sterile saline was injected to form the control groups. Flow cytometry was performed to measure the proportion of Th17 cells in CD4⁺ T cells in the peripheral blood, spleen, and lung of the mice. The expression of IL-17A, RORγt, and STAT3 mRNA was detected by real-time polymerase chain reaction. Concentrations of IL-6 in the plasma and bronchoalveolar lavage fluid were measured by enzyme-linked immunosorbent assay.

Results

The proportion of Th17 in the peripheral blood and lung tissue in neutropenic IPA mice showed a more significant increase than in non-neutropenic IPA mice (P<0.01). The IL-6 protein also showed the same trend in plasma and bronchoalveolar lavage fluid (P<0.01). Compared with the control groups, the expression of IL-17A at mRNA level in the lung was significantly increased, while RORγt/STAT3 mRNA was significantly decreased in the IPA groups (P<0.01).

Conclusion

The expression of RORγt and STAT3 mRNA in the lung tissue in both groups was significantly decreased. IL-17 may play a negative role in the defense against Aspergillus through uprating IL-6.

Inhibitory effect of celecoxib on agomelatine metabolism in vitro and in vivo

Aim

The aim of this study was to study the effect of celecoxib on agomelatine metabolism in vitro and in vivo.

Methods

Ten healthy male Sprague–Dawley rats were randomly divided into 2 groups: Group A (control group) and Group B (30 mg/kg celecoxib). Then a single dose of 20 mg/kg agomelatine was administered orally 30 min after administration of celecoxib. In an in vitro study, celecoxib with a series of concentrations was added to an incubation mixture containing recombinant human CYP2C9, human or rat liver microsomes to determine the half-maximal inhibitory concentration on the metabolism of agomelatine. Moreover, a mechanism study was performed to determine the inhibitory effect of celecoxib on CYP2C9.

Results

The results showed that a single dose of 30 mg/kg celecoxib significantly increased the area under the concentration-time curve and maximum concentration of agomelatine. In addition, celecoxib inhibited the metabolism of agomelatine in the in vitro studies, which was determined to be by a competitive mechanism on CYP2C9. Those results indicated that celecoxib has an inhibitory effect on the metabolism of agomelatine both in vivo and in vitro.

Conclusion

Thus, more attention should be paid when celecoxib is administered combined with agomelatine.

Functional assessment of CYP3A4 allelic variants on lidocaine metabolism in vitro

Aim

Human cytochrome P450 3A4 is the most abundant isoform of P450 enzyme in the liver. It plays an important role in the metabolism of wide variety of xenobiotic and endogenous substrates. So far, there are few reports about the functional characterization of CYP3A4 variants in terms of specific substrates. The aim of this study was to systematically investigate the genetic polymorphisms of 23 CYP3A4 alleles and evaluate their catalytic activities on the metabolism of lidocaine in vitro.

Methods and results

The wild-type and 22 CYP3A4 variants were expressed in Spodoptera frugiperda 21 insect cells. Then the insect microsomes were incubated with the CYP3A4-specific substrate lidocaine. Reactions were performed with 50–3,000 µM for 60 min at 37°C. Lidocaine and its metabolite monoethylglycinexylidide were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry system. Of the 23 CYP3A4 allelic variants tested, 2 variants (CYP3A4*17 and CYP3A4*30) had no detectable enzyme activity; and 5 variants (CYP3A4*2, CYP3A4*5, CYP3A4*9, CYP3A4*16 and CYP3A4*24) showed significantly decreased intrinsic clearance values compared with wild-type CYP3A4*1.

Conclusion

As the first study of all these CYP3A4 alleles for lidocaine metabolism, our results in vitro assessment may provide novel insights into the allele-specific and substrate-specific activity of CYP3A4 and may also offer a reference to the personalized treatment of lidocaine in a clinical setting.

Role of cytochrome P450 2D6 genetic polymorphism in carvedilol hydroxylation in vitro

Cytochrome P450 2D6 (CYP2D6) is a highly polymorphic enzyme that catalyzes the metabolism of a great number of therapeutic drugs. Up to now, >100 allelic variants of CYP2D6 have been reported. Recently, we identified 22 novel variants in the Chinese population in these variants. The purpose of this study was to examine the enzymatic activity of the variants toward the CYP2D6 substrate carvedilol in vitro. The CYP2D6 proteins, including CYP2D6.1 (wild type), CYP2D6.2, CYP2D6.10, and 22 other novel CYP2D6 variants, were expressed from insect microsomes and incubated with carvedilol ranging from 1.0 μM to 50 μM at 37°C for 30 minutes. After termination, the carvedilol metabolites were extracted and detected using ultra-performance liquid chromatography tandem mass-spectrometry. Among the 24 CYP2D6 variants, CYP2D6.92 and CYP2D6.96 were catalytically inactive and the remaining 22 variants exhibited significantly decreased intrinsic clearance values (ranging from ~25% to 95%) compared with CYP2D6.1. The present data in vitro suggest that the newly found variants significantly reduced catalytic activities compared with CYP2D6.1. Given that CYP2D6 protein activities could affect carvedilol plasma levels, these findings are greatly relevant to personalized medicine.

Risk of adverse events with bevacizumab addition to therapy in advanced non-small-cell lung cancer: a meta-analysis of randomized controlled trials

Background

Bevacizumab, a monoclonal antibody against vascular endothelial growth factor ligand, has shown survival benefits in the treatment of many types of malignant tumors, including non-small-cell lung cancer (NSCLC). We conducted this systematic review and meta-analysis to investigate the risk of the most clinically relevant adverse events related to bevacizumab in advanced NSCLC.

Methods

Databases from PubMed, Web of Science, and Cochrane Library up to August 2015, were searched to identify relevant studies. We included prospective randomized controlled Phase II/III clinical trials that compared therapy with or without bevacizumab for advanced NSCLC. Summary relative risk (RR) and 95% confidence intervals were calculated using random effects or fixed effects according to the heterogeneity among included trials.

Results

A total of 3,745 patients from nine clinical trials were included in the meta-analysis. Summary RRs showed a statistically significant bevacizumab-associated increased risk in three of the adverse outcomes studied: proteinuria (RR =7.55), hypertension (RR =5.34), and hemorrhagic events (RR =2.61). No statistically significant differences were found for gastrointestinal perforation (P=0.60), arterial and venous thromboembolic events (P=0.35 and P=0.92, respectively), or fatal events (P=0.29).

Conclusion

The addition of bevacizumab to therapy in advanced NSCLC did significantly increase the risk of proteinuria, hypertension, and hemorrhagic events but not arterial/venous thromboembolic events, gastrointestinal perforation, or fatal adverse events.

Genetic variations of human CYP2D6 in the Chinese Han population

Aim: The purpose of this study was to determine the genetic polymorphisms of the CYP2D6 gene and to elucidate the allele distribution pattern in the Chinese Han population. Materials & methods: We used PCR and bidirectional sequencing methods to analyze all nine exons of the CYP2D6 gene in 2129 unrelated, healthy Chinese Han subjects from two geographical locations in China: the northern and southern regions. Results: In total, 165 mutated sites were detected in 2129 participants, of which 67 sites were reported for the first time. Among these novel mutation sites, 22 were nonsynonymous and 12 were named as novel alleles (*87–*93, *94A, *94B and *95–*98) by the Human CYP Allele Nomenclature Committee. In addition, 29 previously reported alleles and 84 genotypes were also detected in 1954 volunteers. Functional prediction of novel variants revealed that eight variants might have a deleterious effect on CYP2D6. Linkage disequilibrium analysis and tagSNP selection were performed separately. By using these methods, distinct differences were found between the two regions. Conclusion: This study provides the most comprehensive data concerning CYP2D6 polymorphisms in the Chinese Han population to date and increases the number of known alleles; these findings may greatly contribute to the development of personalized medicine for the Chinese Han population.

Original submitted 1 January 2013; Revision submitted 14 August 2013

Effect of Repeated Wuniu Early Tea Administration on the CYP450 Activity Using a Cocktail Method

Wuniu early tea (Camellia sinensis) is an important beverage consumed in China. Up to date, a lot of methods for identifying and chemical analysing have been done. However, there is no report on the effects of Wuniu early tea on cytochrome P450 isozymes. Therefore, the present objective of our study was to evaluate the potential effects of Wuniu early tea on cytochrome P450 isozymes P2C9, P1A2, P2C19 and P2B6 in rats with a cocktail approach including, matching probe drugs of tolbutamide, phenacetin, omeprazole and bupropion. These four probe drugs were simultaneously administered to rats after repeated Wuniu early tea administration. The pharmacokinetics of the probes in the plasma was simultaneous determined by high-performance liquid chromatography-mass spectrometry. The t_1/2 and AUC_(0-∞) of tolbutamide increased significantly and CL_z decreased remarkably in test rats after repeated Wuniu early tea administration. However, the main pharmacokinetic parameters of the other three probe drugs were not significantly different between control and test rats. The findings in this study suggested that Wuniu early tea could inhibit cytochrome P2C9 while did not influence on cytochrome P1A2, cytochrome P2C19 and cytochrome P2B6.

Therapeutic drug monitoring in voriconazole-associated hyponatremia

Voriconazole is a second generation triazole antifungal agent and the first choice therapy for invasive aspergillosis (IA). Although voriconazole may be associated with many adverse events, hyponatremia has been rarely reported which potentially could result in death. Therapeutic drug monitoring (TDM) and individualization of therapy by measuring voriconazole plasma concentrations improved the efficacy and safety in patients. We report the effect of TDM to adjust voriconazole dosage in a voriconazole-related hyponatremia patient.

Effects of repeated allopurinol administration on rat cytochrome P450 activity

Allopurinol is a popular and widely-prescribed anti-hyperuricemic agent that has been implicated in drug interactions with substrates of several cytochrome P450 (CYP) enzymes. The effect of repeated allopurinol administration (20 mg/kg, once daily for 14 days) on metabolic activity of CYP was assessed in rats. This was a randomized, double-blind, two-way crossover study with a 4-week washout period between phases. The substrates used in this study were phenacetin (CYP1A2), tolbutamide (CYP2C9), omeprazole (CYP2C19) and dextromethorphan (CYP2D6). Validated HPLC-MS/MS was used to quantify all compounds. Our study showed that allopurinol administration inhibited CYP1A2 activity, causing a significant increase in AUC (0-infinity) (P < 0.01) and t1/2 (P < 0.05) of phenacetin, and a distinct decline in CL (P < 0.01). However, there were no significant differences of another three probe drugs in plasma concentrations and the corresponding pharmacokinetic parameters between the allopurinol-treated and normal saline-treated rats. The findings in this study suggested that allopurinol could inhibit CYP1A2 but did not influence CYP2C9, CYP2C19 and CYP2D6 enzymes.