The effect of icotinib or apatinib on the pharmacokinetic profile of oxycodone in rats and the underlying mechanism.

This study aimed to investigate the interactions between icotinib/apatinib and oxycodone in rats and to unveil the underlying mechanism. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine oxycodone and its demethylated metabolite simultaneously. In vivo, Sprague-Dawley (SD) male rats were administered oxycodone with or without icotinib or apatinib. Blood samples were collected and subjected to UPLC-MS/MS analysis. An enzyme incubation assay was performed to investigate the mechanism of drug-drug interaction using both rat and human liver microsomes (RLM and HLM). The results showed that icotinib markedly increased the AUC(0-t) and AUC(0-∞) of oxycodone but decreased the CLz/F. The Cmax of oxycodone increased significantly upon co-administration of apatinib. In vitro, the Km value of oxycodone metabolism was 101.7 ± 5.40 µM and 529.6 ± 19.60 µM in RLMs and HLMs, respectively. Icotinib and apatinib inhibited the disposition of oxycodone, with a mixed mechanism in RLM (IC50 = 3.29 ± 0.090 µM and 0.95 ± 0.88 µM, respectively) and a competitive and mixed mechanism in HLM (IC50 = 22.34 ± 0.81 µM and 0.48 ± 0.05 µM, respectively). In conclusion, both icotinib and apatinib inhibit the metabolism of oxycodone in vitro and in vivo. Therefore, the dose of oxycodone should be reconsidered when co-administered with icotinib or apatinib.

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.

Effect of apatinib on the pharmacokinetics of tramadol and O-desmethyltramadol in rats.

Since the combination of anticancer drugs and opioids is very common, apatinib and tramadol are likely to be used in combination clinically. This study evaluated the effects of apatinib on the pharmacokinetics of tramadol and its main metabolite O-desmethyltramadol in Sprague-Dawley (SD) rats and the inhibitory effects of apatinib on tramadol in rat liver microsomes (RLMs), human liver microsomes (HLMs) and recombinant human CYP2D6.1. The samples were determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The in vivo results showed that compared with the control group, apatinib increased the AUC(0-t), AUC(0-∞) and Cmax values of tramadol and O-desmethyltramadol, and decreased the values of VZ/F and CLz/F. In addition, the MRT(0-t), MRT(0-∞) values of O-desmethyltramadol were increased. In vitro, apatinib inhibited the metabolism of tramadol by a mixed way with IC50 of 1.927 µM in RLMs, 2.039 µM in HLMs and 15.32 µM in CYP2D6.1. In summary, according to our findings, apatinib has a strong in vitro inhibitory effect on tramadol, and apatinib can increase the analgesic effect of tramadol and O-desmethyltramadol in rats.

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.

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.

CYP2D6 gene polymorphism and apatinib affect the metabolic profile of fluvoxamine.

This study aimed 1) to investigate the influence of CYP2D6 variants on the catalyzing of fluvoxamine, and 2) to study the interaction between fluvoxamine and apatinib. An enzymatic reaction system was setup and the kinetic profile of CYP2D6 in metabolizing fluvoxamine was determined. In vivo, drug-drug interaction was investigated using Sprague-Dawley (SD) rats. Fluvoxamine was given gavage with or without apatinib. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to determine the concentrations of fluvoxamine and desmethyl-fluvoxamine. The results demonstrated that the relative clearance rates of CYP2D6.A5V, V104A, D337G, F164L, V342M, R440C and R497C increased significantly compared with CYP2D6.1, ranging from 153.626% ± 6.718% to 394.310% ± 33.268%. The activities of other variants reduced to different extent, or even lost function, but there was no statistical difference. The IC50 of apatinib against fluvoxamine disposition was determined, which is 0.190 µM in RLM and 6.419 µM in HLM, respectively. In vivo, apatinib can enhance the plasma exposure of fluvoxamine remarkably characterized by increased AUC, Tmax and Cmax. Meanwhile, the produce of desmethyl fluvoxamine was dramatically inhibited, both AUC and Cmax decreased significantly. Mechanistically, apatinib inhibit the generation of fluvoxamine metabolite with a mixed manner both in RLM and HLM. Furthermore, there were differences in the potency of apatinib in suppressing fluvoxamine metabolism among CYP2D6.1, 2 and 10. In conclusion, CYP2D6 gene polymorphisms and drug-drug interaction can remarkably affect the plasma exposure of fluvoxamine. The present study provides basis data for guiding individual application of fluvoxamine.

Development and Validation of a UHPLC-MS/MS Method for Quantitation of Almonertinib in Rat Plasma: Application to an in vivo Interaction Study Between Paxlovid and Almonertinib.

Almonertinib was approved for the first-line treatment of advanced NSCLC patients with EGFR-TKI-sensitive genetic mutations by National Medical Products Administration (NMPA) in 2021.The purpose of this study was to establish and validate a fast, accurate, stable and facile ultra-performance liquid chromatography-tandem mass spectrometry method for the quantification of almonertinib in rat plasma, it was employed to explore the effect of Paxlovid on the pharmacokinetics of almonertinib in rats. Zanubrutinib was used as an internal standard (IS), and the plasma samples were prepared by the protein precipitation method using acetonitrile. Chromatographic separation was carried out on a Shimadzu LC-20AT ultra-performance liquid chromatography system using a Shim-pack velox C18 (2.1× 50 mm, 2.7 µM) column. The mobile phase consisted of methanol and 0.1% formic acid-water. Mass spectrum analysis was executed using Shimadzu 8040 Triple quadrupole mass spectrometry. The precursor and product ions of the analyte and internal standard were detected in multiple reaction monitoring (MRM) mode. The typical fragment ions were m/z 526.20 → 72.10 for almonertinib and m/z 472.15 → 290.00 for zanubrutinib (IS). The method was validated to have good linearity for quantifying almonertinib in rat plasma from 0.1-1000 ng/ml (R2 = 0.999), and the LLOQ was 0.1 ng/ml. The validity of this method was sufficiently verified for selectivity, specificity, extraction recovery, matrix effect, accuracy, precision and stability. The validated UHPLC-MS/MS method was successfully applied to the drug interaction study of almonertinib with Paxlovid in rats. Paxlovid significantly inhibits the metabolism of almonertinib and increased the exposure of almonertinib. This study can help us to understand the metabolic profile of almonertinib better, and further human trials should be conducted to validate the results.

The effect of CYP3A4 genetic polymorphism and drug interaction on the metabolism of istradefylline.

AIM: This study investigated into the effect of CYP3A4 genetic polymorphism on istradefylline metabolism. Moreover, the potential drug-drug interaction with istradefylline was determined as well as underlied mechanism. METHOD: In vitro, enzymatic reaction was performed to determine the kinetic parameters of CYP3A4 and its variants on catalyzing istradefylline. Meanwhile, the rat liver microsomes incubation assay was applied to screen interacting drugs. In vivo, SD rats were used to investigate the selected drug interaction. UPLC-MS/MS was used to detect the metabolite M1. RESULT: The results demonstrated that the relative clearance rate of CYP3A4.29 decrease significantly compared with CYP3A4.1. But there is no statistically diverse in activities among CYP3A4.1, 2 and 3. The relative clearance rates of the remaining variants are significantly decreased compared with CYP3A4.1. In addition, 148 drugs were screened to determine the potential interaction with istradefylline, among which calcium channel blockers were identified. It's indicated that nimodipine has a significant inhibitory effect on metabolizing istradefylline with IC50 of 6.927 ± 0.372 µM, which via competitive and non-competitive mixed mechanism. In vivo, when istradefylline and nimodipine was co-administered to SD rats, we found the main pharmacokinetic parameters of M1 reduced remarkably, including AUC, MRT, Cmax and CLz/F. CONCLUSION: CYP3A4 genetic polymorphism and nimodipine affect the metabolism of istradefylline. Thus, the present study provided reference data for clinical individualized medicine of istradefylline.

The effect of anlotinib on the pharmacokinetic profile of oxycodone and the underlying mechanism.

PURPOSE: Cancer patients experience pain during medical treatment. Therefore, anticancer drugs and painkillers are often prescribed together. This study aims to determine the interaction between anlotinib and oxycodone and reveal the underlying mechanism. METHODS: UPLC-MS/MS, an efficient and sensitive method, was used for the simultaneous determination of oxycodone and oxycodone metabolites. Sprague-Dawley rats were given oxycodone with or without anlotinib. Then, UPLC-MS/MS was used to determine the blood concentration of oxycodone. To study the interaction mechanism, rat and human liver microsomes (HLMs) were used for determining enzyme kinetics. RESULTS: Long-term administration of oxycodone combined with anlotinib resulted in significantly increased pharmacokinetic parameters AUC(0-t), AUC(0-∞), and Cmax for oxycodone, indicating that anlotinib inhibited oxycodone. In vitro kinetic measurements indicated that anlotinib inhibited the metabolism of oxycodone through a mixed mechanism. Further studies indicated that in HLMs, anlotinib strongly inhibited the metabolism of oxycodone. CONCLUSION: This study showed that anlotinib inhibited the metabolism of oxycodone both in vitro and in vivo. It is recommended that the dose of oxycodone should be reconsidered when oxycodone is combined with anlotinib in clinical practice.

Inhibitory effects of fluoxetine and duloxetine on the pharmacokinetics of metoprolol in vivo and in vitro.

Depression is common among people with cardiovascular diseases. Therefore, the combined use of antidepressants and cardiovascular drugs is very common, which increases the possibility of drug interaction. Simultaneously compare the effects of duloxetine and fluoxetine on metoprolol metabolism, and provide evidence-based guidance for medication safety. Sprague-Dawley rats were randomly divided into three groups: group A (10.3 mg/kg metoprolol alone), group B (10.3 mg/kg metoprolol + 6.2 mg/kg fluoxetine), and group C (10.3 mg/kg metoprolol + 6.2 mg/kg duloxetine). Tail vein blood was collected and subjected to the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection. Moreover, in vitro inhibition of fluoxetine and duloxetine were assessed by incubating liver microsomes and CYP2D6.1 with metoprolol. In in vivo study, the administration of fluoxetine or duloxetine significantly increased the AUC(0-𝑡) and AUC(0-∞) of metoprolol (P < 0.05). Differences between fluoxetine and duloxetine in plasma concentration were also investigated, and their pharmacokinetic parameters such as AUC(0-𝑡) and AUC(0-∞) were significantly distinct (P < 0.05). In vitro, fluoxetine and duloxetine inhibited the metabolism of metoprolol via mixed competitive mechanism of cytochrome P450. IC50 values of fluoxetine and duloxetine were 12.86 and 2.51 µM, respectively. Moreover, the metabolism rate of metoprolol was inhibited to 19.62% and 17.14% in recombinant human CYP2D6.1 by fluoxetine and duloxetine, respectively. Duloxetine showed a more significant inhibitory potential compared to fluoxetine in vitro, but the main pharmacokinetic parameters of fluoxetine and duloxetine revealed differences in inhibiting metoprolol metabolism in vivo.

The Influence of CYP3A4 Genetic Polymorphism and Proton Pump Inhibitors on Osimertinib Metabolism.

The aim of this study was to 1) investigate the effects of 27 CYP3A4 variants on the metabolism of osimertinib and 2) study the interactions between osimertinib and others as well as the underlying mechanism. A recombinant human CYP3A4 enzymatic incubation system was developed and employed to determine the kinetic profile of CYP3A4 variants. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was applied to detect the concentration of the main metabolite, AZ5104. The results demonstrated that the relative clearance rates of CYP3A4.19, 10, 18, 5, 16, 14, 11, 2, 13, 12, 7, 8, and 17 in catalyzing osimertinib were significantly reduced to a minimum of 25.68% compared to CYP3A4.1, while those of CYP3A4.29, 32, 33, 28, 15, 34, and 3 were obviously enhanced, ranging from 114.14% to 284.52%. The activities of the remaining variants were almost equal to those of CYP3A4.1. In addition, 114 drugs were screened to determine the potential interaction with osimertinib based on the rat liver microsome (RLM) reaction system. Sixteen of them inhibited the production of AZ5104 to 20% or less, especially proton pump inhibitors, among which the IC50 of rabeprazole was 6.49 ± 1.17 µM in RLM and 20.39 ± 2.32 µM in human liver microsome (HLM), with both following competitive and non-competitive mixed mechanism. In an in vivo study, Sprague-Dawley (SD) rats were randomly divided into groups, with six animals per group, receiving osimertinib with or without rabeprazole, omeprazole, and lansoprazole. We found that the AUC(0-t), AUC(0-∞), and Cmax of osimertinib decreased significantly after co-administration with rabeprazole orally, but they increased remarkably when osimertinib was administered through intraperitoneal injection. Taken together, our data demonstrate that the genetic polymorphism and proton pump inhibitors remarkably influence the disposition of osimertinib, thereby providing basic data for the precise application of osimertinib.

Functional evaluation of cyclosporine metabolism by CYP3A4 variants and potential drug interactions.

The aim of this study is to investigate the effects of CYP3A4 genetic polymorphisms on the metabolism of cyclosporine (CsA) in vitro and identify drugs that interact with CsA. An enzymatic incubation system was developed to evaluate the kinetic parameters of CYP3A4 on CsA catalysis. A total of 132 drugs were screened to identify potential drug-drug interactions. Sprague-Dawley rats were used to determine the interaction between CsA and nimodipine and nisoldipine. The metabolite AM1 was measured by ultra-performance liquid chromatography-tandem mass spectrometry. The results demonstrate that 16 CYP3A4 variants (CYP3A4.7, 8, 9, 12, 13, 14, 16, 18, 19, 23, 24, 28, 31, 32, 33, and 34) have a lower metabolic capacity for CsA, ranging from 7.19% to 72.10%, than CYP3A4.1. In contrast, the relative clearance rate of CYP3A4.5 is significantly higher than that of CYP3A4.1. Moreover, CYP3A4.20 loses its catalytic ability, and five other variants have no significant difference. A total of 12 drugs, especially calcium channel blockers, were found to remarkably inhibit the metabolism of CsA with an inhibitory rate of over 80%. Nimodipine inhibits the activity of CsA in rat liver microsomes with an IC50 of 20.54 ± 0.93 µM, while nisoldipine has an IC50 of 16.16 ± 0.78 µM. In in vivo, three groups of Sprague-Dawley rats were administered CsA with or without nimodipine or nisoldipine; the AUC(0-t) and AUC(0-∞) of CsA were significantly increased in the nimodipine group but not obviously in the nisoldipine group. Mechanistically, the inhibition mode of nimodipine on cyclosporine metabolism is a mixed inhibition. Our data show that gene polymorphisms of CYP3A4 and nimodipine remarkably affect the metabolism of CsA, thus providing a reference for the precise administration of CsA.

Inhibitory effect of resveratrol on the pharmacokinetics of ticagrelor in vivo and in vitro.

This study was to evaluate the effect of resveratrol on the pharmacokinetics of ticagrelor in rats and the metabolism of ticagrelor in human cytochrome P450 (CYP) 3A4 (CYP3A4) and liver microsomes. Eighteen Sprague-Dawley rats were randomly divided into three groups: group A (control group), group B (50 mg/kg resveratrol), and group C (150 mg/kg resveratrol). After 30 min administration of resveratrol, a single dose of ticagrelor (18 mg/kg) was administered orally. The in vitro experiment was performed to examine the influence of resveratrol on ticagrelor metabolism in CYP3A4*1, human, and rat liver microsomes. Serial biological samples were assayed by validated ultra high-performance liquid chromatography - tandem mass spectrometer methods. For the in vivo study, the area under the concentration-time curve and mean peak plasma concentrations of ticagrelor in group B and C appeared to be significantly higher than the control group, while volume of distribution in terminal phase and apparent clearance of ticagrelor in group B and C were significantly decreased. For the in vitro study, resveratrol exhibited an inhibitory effect on CYP3A4*1, human and rat liver microsomes. The half-maximal inhibitory concentration values of resveratrol were 56.75 µM, 69.07 µM, and 14.22 µM, respectively. Our results indicated that resveratrol had an inhibitory effect on the metabolism of ticagrelor in vitro and in vivo. Further research should focus on the clinical combination of resveratrol with ticagrelor, and ticagrelor plasma concentration should be monitored to avoid the occurrence of adverse reaction.