The Effect of α‐Mangostin on the Pharmacokinetic Profile of Tofacitinib in Rats Both In Vitro and In Vivo

Context Naringenin and tofacitinib are often used together for treatment of rheumatoid arthritis in Chinese clinics. Objective This experiment investigates the effect of naringenin on the pharmacokinetics of tofacitinib in rats. Materials and methods Twelve Sprague-Dawley rats were randomly divided into two groups (experimental group and control group). The experimental group was pre-treated with naringenin (150 mg/kg/day) for two weeks before dosing tofacitinib, and equal amounts of CMC-Na solution in the control group. After a single oral administration of 5 mg/kg of tofacitinib, 50 μL blood samples were directly collected into 1.5 mL heparinized tubes via the caudal vein at 0.083, 0.5, 1, 2, 3, 4, 6, 8, 10, 12 and 24 h. The plasma concentration of tofacitinib was quantified by UPLC/MS–MS. Results Results indicated that naringenin could significantly affect the pharmacokinetics of tofacitinib. The AUC0–24 of tofacitinib was increased from 1222.81 ± 222.07 to 2016.27 ± 481.62 ng/mL/h, and the difference was significant (p < 0.05). Compared with the control group, the T max was increased from 0.75 ± 0.29 to 3.00 ± 0.00 h (p < 0.05), and the MRT(0–24) was increased from 4.90 ± 0.51 to 6.57 ± 0.66 h (p < 0.05), but the clearance was obviously decreased from 4.10 ± 0.72 to 2.42 ± 0.70 L/h/kg (p < 0.05) in experimental group. Although the C max and t 1/2 of tofacitinib were increased, there were no significant differences (p > 0.05). Conclusions This research demonstrated a drug-drug interaction between naringenin and tofacitinib possibly when preadministered with naringenin; thus, we should pay attention to this possibility in the clinic.

The aim of this study was to investigate the impact of calcium channel blockers (CCBs) and antihypertensive traditional Chinese medicine (TCM) on the metabolism of quetiapine. In vitro, two incubation systems of rat liver microsomes (RLM) and human liver microsomes (HLM) were established and optimized to explore potential interactions between five kinds CCBs (nicardipine, dilthiazem, lercanidipine, nimodipine, nitrendipine), five kinds antihypertensive TCM (quercetin, fangchinoline, apigenin, tetrandrine, and berberine) and quetiapine, and to evaluate their underlying inhibition mechanisms. In vivo, Sprague-Dawley rats were used to assess the interaction between quetiapine and nicardipine. The results showed that nicardipine had the highest inhibition rate (79.22%) against quetiapine metabolism among those drugs screened. The half-maximal inhibitory concentration (IC50) values for the inhibition of quetiapine metabolism by nicardipine in RLM and HLM were similar, at 10.29 ± 0.06 μM and 13.23 ± 0.37 μM, respectively. In RLM, nicardipine exhibited a mixed mechanism of competitive and non-competitive inhibition, while in HLM, it displayed a non-competitive and un-competitive inhibition mechanism. In vivo results indicated that nicardipine could significantly increase the main pharmacokinetic parameters AUC(0-t), , and Cmax of quetiapine, but decrease the AUC(0-t) of its metabolite N-desalkylquetiapine. The findings of this study suggested that nicardipine had inhibited the metabolism of quetiapine, suggesting the dose adjustment or therapeutic drug monitoring of quetiapine should be conducted to achieve individualized therapy.

Terminalia arjuna Wight & Arn. (Combretaceae) is a tree having an extensive medicinal potential in cardiovascular disorders. T. arjuna bark extract has been reported to play a significant role as a cardiac stimulant for its beneficial effects in angina. Herb - drug interactions (HDI) are one of the most important clinical concerns in the concomitant consumption of herbs and prescription drugs. Our study was to investigate the in vitro CYP2D inhibition potential of Terminalia arjuna (T. arjuna) extracts in rat liver microsomes and to study the influence of aqueous bark extract of T. arjuna on the oral pharmacokinetics and pharmacodynamics of metoprolol succinate in rats. The CYP2D inhibition potential of herbal extracts of T. arjuna was investigated in rat liver microsomes. Pharmacokinetic-pharmacodynamic interaction of aqueous extract of T. arjuna with metoprolol succinate was investigated in rats. The ethyl acetate, alcoholic &amp; aqueous bark extracts of T. arjuna showed potent reversible non-competitive inhibition CYP2D enzyme in rat liver microsomes with IC50 values less than 40 μg/mL. Arjunic acid, arjunetin and arjungenin did not show significant inhibition of CYP2D enzyme in rat liver microsomes. Pharmacokinetic studies showed that aqueous bark extract of T. arjuna led to a significant reduction (P < 0.05) in AUC0-24h and Cmax of metoprolol succinate in rats, when co-administered. Pharmacodynamic studies reveal a significant reduction in therapeutic activity of metoprolol succinate on co-administration with aqueous bark extract of T. arjuna. Based on our in vitro and in vivo findings and until further clinical drug interaction experiments are conducted, the co-administration of drugs, especially those primarily cleared via CYP2D catalyzed metabolism, with T. arjuna extracts should be done with caution.

To study the potential drug-drug interactions between tofacitinib and baohuoside I and to provide the scientific basis for rational use of them in clinical practice. A total of eighteen Sprague-Dawley rats were randomly divided into three groups: control group, single-dose group (receiving a single dose of 20 mg/kg of baohuoside I), and multi-dose group (receiving multiple doses of baohuoside I for 7 days). On the seventh day, each rat was orally administered with 10 mg/kg of tofacitinib 30 minutes after giving baohuoside I or vehicle. Blood samples were collected and determined using UPLC-MS/MS. In vitro effects of baohuoside I on tofacitinib was investigated in rat liver microsomes (RLMs), as well as the underlying mechanism of inhibition. The semi-inhibitory concentration value (IC50) of baohuoside I was subsequently determined and its inhibitory mechanism against tofacitinib was analyzed. Furthermore, the interactions between baohuoside I, tofacitinib and CYP3A4 were explored using Pymol molecular docking simulation. The administration of baohuoside I orally has been observed to enhance the area under the concentration-time curve (AUC) of tofacitinib and decrease the clearance (CL). The observed disparity between the single-dose and multi-dose groups was statistically significant. Furthermore, our findings suggest that the impact of baohuoside I on tofacitinib metabolism may be a mixture of non-competitive and competitive inhibition. Baohuoside I exhibit an interaction with arginine (ARG) at position 106 of the CYP3A4 enzyme through hydrogen bonding, positioning itself closer to the site of action compared to tofacitinib. Our study has demonstrated the presence of drug-drug interactions between baohuoside I and tofacitinib, which may arise upon pre-administration of tofacitinib. Altogether, our data indicated that an interaction existed between tofacitinib and baohuoside I and additional cares might be taken when they were co-administrated in clinic.

Effects of CYP2C9 genetic polymorphism and drug-drug interactions on trimethoprim metabolism.

Context Ambrisentan is an oral endothelin-receptor antagonist (ERA). However, there is no report on the interaction between ambrisentan and shikonin. Objective To investigate the effect of shikonin on ambrisentan metabolism in vivo and in vitro. Materials and methods This study developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of ambrisentan and (S)-4-hydroxymethyl ambrisentan in rat plasma. Twelve male Sprague-Dawley (SD) rats were divided into two groups (n = 6): the control group and shikonin (20 mg/kg) group. The pharmacokinetics of ambrisentan (2.5 mg/kg) were investigated after 30 min. Additionally, human and rat liver microsomes were used to investigate the herb-drug interaction. Results The UPLC-MS/MS method was shown to be accurate, precise and reliable, and was successfully applied to the herb-drug interaction study of ambrisentan with shikonin. When co-administrated with 20 mg/kg shikonin, the C max and AUC(0–∞) of ambrisentan were significantly increased by 44.96 and 16.65%, respectively (p < 0.05). In addition, there were modest decreases in (S)-4-hydroxymethyl ambrisentan Cmax and AUC(0–∞) in the presence of shikonin (p < 0.05), which indicated that these results were in accordance with the inhibition of shikonin on ambrisentan metabolism. Moreover, enzyme kinetic study indicated that shikonin had an inhibitory effect on human and rat microsomes where the IC50 values of shikonin were 5.865 and 6.358 μM, respectively. Conclusions Our study indicated that shikonin could inhibit ambrisentan metabolism. Further studies need to be carried out to verify whether similar interaction truly apply in humans and whether this interaction has clinical significance.

Herb–drug interaction between an anti-HIV Chinese herbal SH formula and atazanavir in vitro and in vivo

The combination of Salvia miltiorrhiza (Danshen) and rivaroxaban is a promising treatment option in clinical practice in China, but the herb–drug interaction between Danshen and rivaroxaban remains unclear. Therefore, this study aims to reveal the interaction between Danshen and rivaroxaban. We not only investigated the inhibitory properties of Danshen tablet on rivaroxaban metabolism in rat and human liver microsomes but also evaluated the inhibitory effects of Danshen tablet and its eight active components (dihydrotanshinone I, tanshinone I, tanshinone IIA, cryptotanshinone, danshensu, salvianolic acid A, salvianolic acid B, and salvianolic acid C) on cytochrome P450 (CYP) enzymes. The results showed that Danshen tablet potently inhibited the metabolism of rivaroxaban in rat and human liver microsomes. In the CYP inhibition study, we found that dihydrotanshinone I, the active component of Danshen tablet, potently inhibited the activities of rat CYP3A and CYP2J, with IC50 values at 13.85 and 6.39 μM, respectively. In further inhibition kinetic study, we found that Danshen tablet is a mixed inhibitor in rivaroxaban metabolism in rat and human liver microsomes, with the Ki value at 0.72 and 0.25 mg/ml, respectively. In conclusion, there is a potential interaction between Danshen tablet and rivaroxaban. Danshen tablet inhibits the metabolism of rivaroxaban, which may be because its lipid-soluble components such as dihydrotanshinone I strongly inhibit the activities of CYP enzymes, especially CYP3A and CYP2J. Therefore, when Danshen tablet and rivaroxaban are used simultaneously in the clinic, it is necessary to strengthen the drug monitoring of rivaroxaban and adjust the dosage.

Inhibitory effects of traditional Chinese medicine colquhounia root tablet on the pharmacokinetics of tacrolimus in rats

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 ± 0.96μM in RLM and 1.52 ± 0.038μM 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 (30mg/kg alectinib alone), the AUC(0-t), AUC(0-∞), Tmax and Cmax of alectinib administered in combination with 6mg/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.

1,3-Butadiene is carcinogenic in B6C3F1 mice and Sprague-Dawley rats, and has been classified as a probable human carcinogen. The genetic basis for butadiene carcinogenicity is likely mediated by its metabolite, 1,2:3,4-diepoxybutane (BDE). Oxidation of butadiene to 1,2-epoxy-3-butene (BMO) and further activation to BDE is catalysed by cytochrome P450 (CYP) isozymes. The production of BMO from butadiene is mediated by CYP2E1 and, at high butadiene concentrations, by CYP2A6. The purpose of the present study was to identify which human CYP isozymes have the ability to oxidize BMO to BDE, and to determine the extent to which this reaction occurs in B6C3F1 mouse, Sprague-Dawley rat, and human liver microsomes. Of the human cDNA-expressed CYP isozymes tested, only CYP2E1 formed detectable concentrations of BDE at 80 microM BMO. CYP2E1 and CYP3A4 were active at 5.0 mM BMO. Interindividual and interspecies variation in the initial rate of oxidation of 80 microM BMO to BDE was determined using 10 samples of human liver microsomes and single pooled samples from rats and mice. Those experiments revealed a 60-fold variation in activity among 10 human liver samples (range: 0.005-0.324 nmol/mg protein/min). Rates of BMO oxidation for mouse and rat liver microsomes were 0.473 and 0.166 nmol/mg protein/min, respectively. Apparent kinetic constants for the oxidation of BMO to BDE by four human microsomal preparations, and pooled samples from mice and rats were estimated from detailed investigations of BMO oxidation at various BMO substrate concentrations. Apparent Km for the human liver samples ranged from 0.304-0.880 mM, and Vmax values ranged from 0.38 to 1.2 nmol/mg protein/min. The apparent values of Km and Vmax for mouse liver microsomes were 0.141 +/- 0.007 mM (mean +/- SE) and 1.303 +/- 0.141 nmol/mg protein/min, respectively. For rat liver microsomes, apparent Km and Vmax were 0.145 +/- 0.036 mM and 0.408 +/- 0.031 nmol/mg protein/min, respectively. Measured rates of BDE formation correlated well with CYP2E1 protein concentrations in the human microsome samples. These results implicate human CYP2E1 as a hepatic isoform responsible for the oxidation of BMO to BDE at low concentrations of BMO. Moreover, our in vitro results reveal that microsomes prepared from human, rat and mouse liver possess the ability to form BDE from BMO. Previous in vitro results suggest that following exposure to butadiene more BMO would probably be present in mice than in rats or humans. Thus, in mice more BMO would be available for activation to BDE.(ABSTRACT TRUNCATED AT 400 WORDS)

Decision letter: Conserved allosteric inhibition mechanism in SLC1 transporters

Editor's evaluation: Conserved allosteric inhibition mechanism in SLC1 transporters

Terminalia arjuna Wight and Arn. (Combretaceae) is a tree having an extensive medicinal potential in cardiovascular disorders. Triterpenoids are mainly responsible for cardiovascular properties. Aqueous, hydroalcoholic and alcoholic extract of T. arjuna, arjunic acid and arjungenin were examined for their potential to inhibit CYP1A enzyme in rat and human liver microsomes. IC50 values of aqueous, hydroalcoholic and alcoholic extract of T. arjuna was found to be 11.4, 28.9 and 44.6 μg/ml in rat liver microsomes while 30.0, 29.7 and 39.0 μg/ml in human liver microsomes, respectively for CYP1A. However IC50 values of arjunic acid and arjungenin for both rat liver microsomes and human liver microsomes were found to be >50 μM. Arjunic acid and arjungenin did not show inhibition of CYP1A enzyme up to concentrations of 50 μM. These in vitro data indicate that Terminalia arjuna extracts contain constituents that can potently inhibit the activity of CYP1A, which could in turn lead to undesirable pharmacokinetic drug-herb interactions in vivo. Based on the in vitro data, interaction potential of the aqueous extract of Terminalia arjuna orally in rats was investigated. A probe substrate, phenacetin, was used to index the activity of CYP1A. In vivo pharmacokinetic study of coadministration of aqueous extract of Terminalia arjuna and phenacetin, revealed that the aqueous extract did not lead to any significant change in the pharmacokinetic parameters of phenacetin as compared with control group. Though there was no in vivo-in vitro correlation, drug interactions could arise with drugs having a narrow therapeutic range and extensively cleared by CYP1A enzyme, which could lead to undesirable side effects.

As a novel acid-suppressing drug, vonoprazan shows the potential to replace traditional proton-pump inhibitors. With its widespread use, some adverse effects that require further study have emerged due to drug–drug interactions. Our study is the first experiment that evaluated the drug–drug interactions of eleven common cardiovascular drugs that inhibit vonoprazan metabolism in vitro and in vivo. Rat liver microsome incubation and molecular simulation docking were applied to explore the inhibition mechanism. Amlodipine and nifedipine showed inhibitory effects on vonoprazan metabolism in both rat and human liver microsomes in the first evaluation part in vitro. The inhibition mechanism analysis results demonstrated that amlodipine and nifedipine might inhibit the metabolism of vonoprazan by a mixed type of competitive and non-competitive inhibition. However, the pharmacokinetic data of the vonoprazan prototype revealed that amlodipine affected vonoprazan in vivo while nifedipine did not. Thus, more attention should be paid when amlodipine is prescribed with vonoprazan. Furthermore, the changes in its carboxylic acid metabolites MI hinted at a complex situation. Molecular simulation suggested the CYP2B6 enzyme may contribute more to this than CYP3A4, and further inhibitory experiments preliminarily verified this speculation. In conclusion, the use of vonoprazan with cardiovascular drugs, especially amlodipine, should receive particular attention in clinical prescriptions.