Inhibition Of CYP2C9 Research Articles

In Vitro Evidence of Potential Interactions between CYP2C8 and Candesartan Acyl-β-D-glucuronide in the Liver.

Growing evidence suggests that certain glucuronides function as potent inhibitors of CYP2C8. We previously reported the possibility of drug-drug interactions between candesartan cilexetil and paclitaxel. In this study, we evaluated the effects of candesartan N2-glucuronide and candesartan acyl-β-D-glucuronide on pathways associated with the elimination of paclitaxel, including those involving organic anion-transporting polypeptide (OATP) 1B1, OATP1B3, CYP2C8, and CYP3A4. UDP-glucuronosyltransferase (UGT) 1A10 and UGT2B7 were found to increase candesartan N2-glucuronide and candesartan acyl-β-D-glucuronide formation in a candesartan concentration-dependent manner. Additionally, the uptake of candesartan N2-glucuronide and candesartan acyl-β-D-glucuronide by cells stably expressing OATPs is a saturable process with K m of 5.11 and 12.1 μM for OATP1B1 and 28.8 and 15.7 μM for OATP1B3, respectively; both glucuronides exhibit moderate inhibition of OATP1B1/1B3. Moreover, the hydroxylation of paclitaxel was evaluated using recombinant CYP3A4 and CYP3A5. Results show that candesartan, candesartan N2-glucuronide, and candesartan acyl-β-D-glucuronide inhibit the CYP2C8-mediated metabolism of paclitaxel, with candesartan acyl-β-D-glucuronide exhibiting the strongest inhibition (IC50 is 18.9 µM for candesartan acyl-β-D-glucuronide, 150 µM for candesartan, and 166 µM for candesartan N2-glucuronide). However, time-dependent inhibition of CYP2C8 by candesartan acyl-β-D-glucuronide was not observed. Conversely, the IC50 values of all the compounds are comparable for CYP3A4. Taken together, these data suggest that candesartan acyl-β-D-glucuronide is actively transported by OATPs into hepatocytes, and drug-drug interactions may occur with coadministration of candesartan and CYP2C8 substrates, including paclitaxel, as a result of the inhibition of CYP2C8 function. SIGNIFICANCE STATEMENT: This study demonstrates that the acyl glucuronidation of candesartan to form candesartan acyl-β-D-glucuronide enhances CYP2C8 inhibition while exerting minimal effects on CYP3A4, organic anion-transporting polypeptide (OATP) 1B1, and OATP1B3. Thus, candesartan acyl-β-D-glucuronide might represent a potential mediator of drug-drug interactions between candesartan and CYP2C8 substrates, such as paclitaxel, in clinical settings. This work adds to the growing knowledge regarding the inhibitory effects of glucuronides on CYP2C8.

Pharmacodynamic and pharmacokinetic interactions of hydroalcoholic leaf extract of Centella asiatica with valproate and phenytoin in experimental models of epilepsy in rats

Ethnopharmacological relevanceCentella asiatica (CA) is commonly used herbal medicine for treatment of epilepsy. CA has CYP2C9, CYP2D6 and CYP3A4 enzymes inhibition property and used as an adjuvant therapy with conventional antiepileptic drugs (AEDs). That may be responsible for herb-drug interaction. Aim of the studyThe present study was planned to evaluate interactions profile of hydroalcoholic extract Centella asiatica (HECA) with antiepileptic drugs in experimental models of epilepsy in rats. Materials and methodsWistar rats (175–200 g) were used. In the pharmacodynamic interaction study, seizures were induced using pentylenetetrazole (PTZ) (60 mg/kg, i.p.) and maximal electroshock seizure (MES) (70 mA for 0.2 s). The therapeutic and sub-therapeutic doses of valproate (VPA) and phenytoin (PHT) were co-administrated with HECA in PTZ and MES model of seizures respectively. Behavioural parameters were assessed using elevated plus maze test and passive avoidance paradigm. Rat brain oxidative stress parameters were also assessed. In the pharmacokinetic interaction study, the serum levels of the VPA and PHT were estimated at different time intervals by HPLC and pharmacokinetic parameters were analyzed by WinNonlin software. ResultsThe VPA and PHT produced complete protection against seizures in their therapeutic doses but not with sub-therapeutic doses. However, co-administration of HECA with a sub-therapeutic dose of VPA and PHT enhanced the protection of seizures and significantly (p < 0.001) attenuated the seizure induced oxidative stress and cognitive impairment. It also significantly increased (p < 0.001) serum levels of VPA and PHT. The alterations in pharmacokinetic parameters (maximum serum concentration, area under the curve, clearance) of AEDs were also found with co-administration of HECA. ConclusionThe results suggested that co-administration of HECA could improve the therapeutic efficacy of VPA and PHT. But, alteration in pharmacokinetic parameters revel that needs critical medical supervision to avoid any toxic reactions.

Effect of ceritinib on the pharmacokinetics of coadministered CYP3A and 2C9 substrates: a phase I, multicenter, drug\u2013drug interaction study in patients with ALK\u2009+\u2009advanced tumors

PurposeCeritinib is an ALK receptor tyrosine kinase inhibitor approved as first- and second-line treatment in adult patients with ALK + metastatic non-small cell lung cancer (NSCLC). The study investigated the drug–drug interaction (DDI) potential of ceritinib when coadministered with midazolam and warfarin as probe substrates for CYP3A and CYP2C9 activity, respectively.MethodsThis was a phase I, multicenter, open-label, single sequence, crossover DDI study in 33 adult patients with ALK + NSCLC or other advanced tumors. A single dose of a cocktail consisting of midazolam and warfarin was administered with and without concomitant administration of ceritinib. The primary objective was to evaluate the pharmacokinetics of midazolam and warfarin. Secondary objectives included pharmacokinetics, safety, tolerability, overall response rate (ORR), and duration of response (DOR) of ceritinib 750 mg once daily.ResultsCeritinib inhibited CYP3A-mediated metabolism of midazolam, resulting in a markedly increased AUC (geometric mean ratio [90% confidence interval]) by 5.4-fold (4.6, 6.3). Ceritinib also led to an increase in the AUC of S-warfarin by 54% (36%, 75%). The pharmacokinetics and safety profile of ceritinib in this study are consistent with previous reports and no new safety signals were reported. Among the 19 patients with NSCLC, efficacy (ORR: 42.1% and DCR: 63.2%) was similar to that reported previously in studies of pretreated patients with ALK + NSCLC.ConclusionCeritinib is a strong CYP3A inhibitor and a weak CYP2C9 inhibitor. These findings should be reflected as actionable clinical recommendations in the prescribing information for ceritinib with regards to concomitant medications whose pharmacokinetics may be altered by ceritinib.

Pharmacokinetic study on the interaction between pachymic acid and bavachin and its potential mechanism

Context Pachymic acid and bavachin are commonly used drugs in the therapy of lung cancer. Objective The co-administration of pachymic acid and bavachin was investigated to evaluate their potential drug-drug interaction. Materials and methods The pharmacokinetics of bavachin (10 mg/kg) was studied in male Sprague-Dawley (SD) rats in the presence of pachymic acid (5 mg/kg) (n = 6). The rats without pre-treatment of pachymic acid were set as the control and the pre-treatment of pachymic acid was conducted for 7 days before the administration of bavachin. The effect of pachymic acid on the activity of CYP2C9 was also estimated in rat liver microsomes with corresponding probe substrates. Results Pachymic acid influenced the pharmacokinetic profile of bavachin with the increased AUC (32.82 ± 4.61 vs. 19.43 ± 3.26 μg/L/h), the prolonged t 1/2 (3.21 ± 0.65 vs. 2.32 ± 0.28 h), and the decreased CLz/F (307.25 ± 44.35 vs. 523.81 ± 88.67 L/h/kg) in vivo. The metabolic stability of bavachin was enhanced by pachymic acid and the transport of bavachin was inhibited by pachymic acid. Pachymic acid was found to inhibit the activity of CYP2C9 with the IC50 of 21.25 µM as well as the activity of P-gp. Discussion and conclusion The interaction between pachymic acid and bavachin results from the inhibition of CYP2C9 and P-gp. The dose of bavachin should be adjusted when combining with pachymic acid. The study design can be generalized to a broader study population with adjustment in the dose.

DETERMINATION OF PHARMACOKINETIC PARAMETERS AND FACTORS INFLUENCING THE PHARMACOKINETIC PARAMETERS OF PHENYTOIN IN THAI CHILDREN WITH EPILEPSY

Objective: Phenytoin displays nonlinear pharmacokinetics due to the saturation of its’ metabolizing enzymes, thus making dosing adjustments a challenge in clinical practice. However, data on the pharmacokinetic parameters of phenytoin in pediatric patients with epilepsy in Thailand remain lacking. This study aimed to determine the pharmacokinetic parameters of phenytoin, and the factors influencing them in epileptic Thai children using therapeutic drug monitoring data.&#x0D; Methods: Steady state phenytoin plasma concentrations were collected from 96 Thai children with epilepsy aged ≤ 15 y. For individuals having a single steady-state concentration (Css) on one dosage, the Vmax was determined by fixing Km = 4.5 mg/l. For patients with two values for Css with different dosages, the Ludden method was used to determine Vmax and Km. Influences on Vmax and Km by demographic factors including age, sex, weight, serum albumin, and the use of CYP2C9 inducers (carbamazepine, phenobarbital, folic acid, and vigabatrin) and inhibitors (valproic acid and topiramate) were determined by linear mixed-effects regression.&#x0D; Results: The majority of patients had sub-therapeutic plasma concentrations of phenytoin. The Vmax and Km were estimated to be 9.84 mg/kg/d and 2.32 mg/l, respectively. Age and weight significantly influenced Vmax, whereas Km had no significant influencing factors.&#x0D; Conclusion: The Vmax estimated in this study is different from other populations previously reported. Our results suggest that increased phenytoin dosages may be required to achieve optimal concentrations due to the sub-therapeutic concentrations reported here. The results from this study are beneficial for phenytoin dosage individualization in Thai children.

Pogostone inhibits the activity of CYP3A4, 2C9, and 2E1 in vitro

Context Pogostone possesses various pharmacological activities, which makes it widely used in the clinic. Its effect on the activity of cytochrome P450 enzymes (CYP450s) could guide its clinical combination. Objective To investigate the effect of pogostone on the activity of human CYP450s. Materials and methods The effect of pogostone on the activity of CYP450s was evaluated in human liver microsomes (HLMs) compared with blank HLMs (negative control) and specific inhibitors (positive control). The corresponding parameters were obtained with 0–100 μM pogostone and various concentrations of substrates. Results Pogostone was found to inhibit the activity of CYP3A4, 2C9, and 2E1 with the IC50 values of 11.41, 12.11, and 14.90 μM, respectively. The inhibition of CYP3A4 by pogostone was revealed to be performed in a non-competitive and time-dependent manner with the Ki value of 5.69 μM and the KI/Kinact value of 5.86/0.056/(μM/min). For the inhibition of CYP2C9 and 2E1, pogostone acted as a competitive inhibitor with the Ki value of 6.46 and 7.67 μM and was not affected by the incubation time. Discussion and conclusions The inhibitory effect of pogostone on the activity of CYP3A4, 2C9, and 2E1 has been disclosed in this study, implying the potential risk during the co-administration of pogostone and drugs metabolized by these CYP450s. The study design provides a reference for further in vivo investigations to validate the potential interaction.

Clinical evaluation of drug-drug interactions between the cytochrome P450 substrates selexipag and clopidogrel in Japanese volunteers.

The strong cytochrome P450 (CYP) 2C8 inhibitor gemfibrozil has been demonstrated to increase the area under the plasma concentration-time curve from 0 to infinity (AUC0-∞ ) of ACT-333679, an active metabolite of selexipag, by 11-fold. Similarly to gemfibrozil, the CYP2C8 inhibitor clopidogrel increased ACT-333679 concentration by 1.9-fold after a single loading dose (300 mg once daily) and 2.7-fold after repeated treatment with the maintenance dose (75 mg once daily) in Europeans. However, the effects of clopidogrel on the pharmacokinetics of selexipag and ACT-333679 have not been fully elucidated in the Japanese population. We investigated the effect of clopidogrel on the pharmacokinetics of selexipag and ACT-333679 in 14 healthy Japanese volunteers. The concomitant administration of clopidogrel with selexipag did not influence the maximum concentration and AUC0-∞ of selexipag, whereas it significantly increased AUC0-∞ of ACT-333679 by approximately 1.90-fold (90% confidence interval 1.69-2.14) without changing the maximum concentration. When selexipag was administered 1 day after clopidogrel was discontinued, the increase in AUC0-∞ of ACT-333679 was 1.37-fold (90% confidence interval 0.93-2.02), suggesting that, although the inhibitory effect of clopidogrel on CYP2C8 was reduced, it persisted for at least 1 day after withdrawal. Our results demonstrated the impact of clopidogrel on the pharmacokinetics of selexipag and its active metabolite and suggested that selexipag should be carefully prescribed with clopidogrel with dose adjustment or reducing the dosing frequency in Japanese clinical settings.

N-(Methyloxycarbonyl)thiophene sulfonamides as high affinity AT2 receptor ligands

A series of meta-substituted acetophenone derivatives, encompassing N-(alkyloxycarbonyl)thiophene sulfonamide fragments have been synthesized. Several selective AT2 receptor ligands were identified, among those a tert-butylimidazole derivative (20) with a Ki of 9.3 nM, that demonstrates a high stability in human liver microsomes (t½ = 62 min) and in human hepatocytes (t½ = 194 min). This methyloxycarbonylthiophene sulfonamide is a 20-fold more potent binder to the AT2 receptor and is considerably more stable in human liver microsomes, than a previously reported and broadly studied structurally related AT2R prototype antagonist 3 (C38). Ligand 20 acts as an AT2R agonist and caused an AT2R mediated concentration-dependent vasorelaxation of pre-contracted mouse aorta. Furthermore, in contrast to imidazole derivative C38, the tert-butylimidazole derivative 20 is a poor inhibitor of CYP3A4, CYP2D6 and CYP2C9. It is demonstrated herein that smaller alkyloxycarbonyl groups make the ligands in this series of AT2R selective compounds less prone to degradation and that a high AT2 receptor affinity can be retained after truncation of the alkyloxycarbonyl group. Binding modes of the most potent AT2R ligands were explored by docking calculations combined with molecular dynamics simulations.

A Mechanistic Physiologically Based Pharmacokinetic (PBPK) Drug Interaction Model for the Mouse Double Minute 2 (MDM2) Inhibitor KRT-232

Background: KRT-232 is a potent, selective, orally available, targeted inhibitor of human MDM2 homolog interactions with tumor suppressor protein 53 (p53). KRT-232 is under development for treatment of myeloproliferative neoplasms, acute myeloid leukemia and Merkel cell carcinoma. KRT-232 is a highly permeable 568.6 g/mol, monoprotic carboxylic acid (pKa 4.35); elimination involves primarily biliary-fecal excretion of an acyl glucuronide metabolite (M1) and enteric glucuronide hydrolysis with enterohepatic recirculation of parent drug. M1 is a 744.7 g/mol monoprotic acid with pKa 3.32 and 1/5th the MDM2 inhibitory potency of KRT-232. Plasma protein binding (fup) of KRT-232 and M1 were ~0.026 and ~0.006, respectively. Static model drug-drug interaction (DDI) calculations (FDA-CDER. 2020) indicated a potential minor DDI with substrates of cytochrome P450s (CYP) CYP3A4 and CYP2C8, UGT1A1, P-glycoprotein 1 (P-gp) and OATP1B1/3. Here, a 'fit-for-purpose' PBPK model for KRT-232 was developed using physicochemical, preclinical (in vitroandin vivo) and clinical pharmacokinetic (PK) data (KartosData on file; Ye et al.Xenobiotica. 2015; Gluck et al.Invest New Drugs. 2020 [Study A]). Methods:Simcyp Simulator V17 (release 1; 27/11/2017; 17.0.90.0) was used. In vitro kinetic parameters: In vitroKi for competitive inhibition of CYP2C8 was 3.8 and 0.17 µM for KRT-232 and M1, respectively.In vitroKI and kinact for mechanism-based inhibition of CYP3A4 by KRT-232 were 28 µM and 4.14 h-1, respectively. Estimatedin vitroKi values for KRT-232-mediated inhibition of UGT1A1, P-gp, OATP1B1 and OATP1B3, were 1.9, 14.8, 4.9 and 6.9 µM. For M1-mediated inhibition of UGT1A1, OATP1B1 and OATP1B3, values were 2.3, 0.393 and 0.606 µM. Model development and verification:KRT-232 absorption was described by a first-order process; fraction absorbed was assumed to be 100% and the absorption rate constant was manually optimized using observed mean plasma concentration data from Part 1 of Study A. KRT-232 clearance was based onin vitroformation clearance of M1 in human liver microsomes, scaled up 4-fold based on observed oral clearance of KRT-232 (Wood et al.Drug Metab Dispos. 2017). KRT-232 distribution volume was described by a minimal PBPK model. KRT-232 and M1 DDI parameters were based onin vitrodata. M1 clearance was manually optimized using mean observed data from Study A (Part 1, 240 mg dose), and distribution volume was predicted by the Simulator using Method 1 and a full PBPK model. PBPK simulated data were compared with patient PK data collected during Part 2 of Study A. Model application:The model predicted potential DDI after steady state (SS) 240 mg once daily KRT-232 administration with substrates of CYP3A4, CYP2C8, UGT1A1, P-gp and OATP1B1/3. DDI simulations included 100 virtual subjects assigned to 10 virtual trials (N=10 each). Population estimates of geometric mean and median Cmax and AUC0-∞ ratios were generated. A "worst case" sensitivity analysis was performed by using a 10-fold increase inin vitroCYP3A4 interaction potency (KI, EC50) relative to the measuredin vitrovalue. Results:Figure 1shows simulated SS mean and individual observed KRT-232 and M1 concentration data from Part 2 of Study A. SS KRT-232 Cmax, AUC0-24h and t1/2 were predicted within 0.80-1.25-fold of observed PK data and tmax was under-predicted (0.36-fold) by the model (Table 1). M1 Cmax and AUC0-24h were within 0.80-1.25-fold of observed PK data on Day 1 (not shown). M1 Cmax on Day 7 was within 0.80-1.25-fold of observed PK data and SS AUC0-24h, t1/2, and tmax were underpredicted (0.72, 0.79 and 0.61-fold) relative to observed PK data. In all simulated DDIs, no clinically significant interaction was predicted for SS 240 mg doses of KRT-232 since predicted Cmax and AUC0-∞ geometric mean ratio (GMR) changes were less than 1.25-fold (Table 2). The CYP3A4 DDI simulation gave a population GMR (90% CI) for Cmax and AUC0-∞ of 1.07 (1.06, 1.09) and 1.15 (1.12, 1.17), respectively. In a sensitivity check, predicted midazolam Cmax and AUC0-∞ after a 10-fold reduction ofin vitroKI and EC50 were 1.44-fold and 2.18-fold, respectively. Although unlikely, a weak CYP3A4 DDI could not be definitively excluded. Conclusions: Mean plasma exposure of KRT-232 and M1 and inter-individual variability were adequately described by the PBPK model. No clinically significant DDI were predicted based on Cmax and AUC0-∞ GMR changes of less than 1.25-fold. Disclosures Templeton: Certara UK, LTD.:Current Employment.Podoll:IV/PO, LLC:Consultancy.Krejsa:Kartos Therapeutics:Current Employment;AstraZeneca:Current equity holder in publicly-traded company;Seattle Genetics:Current equity holder in publicly-traded company;Acerta Pharma:Current equity holder in private company.Slatter:Kartos Therapeutics:Current Employment;AstraZeneca:Current equity holder in publicly-traded company;Amgen:Divested equity in a private or publicly-traded company in the past 24 months.

Clopidogrel Dosing: Current Successes and Emerging Factors for Further Consideration

This review aimed to evaluate the clinical success of clopidogrel dosing based on CYP2C19 genotype and to identify the relevant additional factors that may be useful for consideration by the clinician when dosing individuals with clopidogrel. The results indicated that genotype-guided dosing in individuals with acute coronary syndrome undergoing percutaneous coronary intervention is frequently practiced, although the advantages remain controversial. Demographic factors, such as age, ethnicity, and some comorbidities, such as diabetes mellitus, can potentially contribute to further refinement of clopidogrel dosage but additional clinical studies to guide these practices are required. Drugs that are CYP2C19 or CYP3A4 inhibitors may reduce the effectiveness of clopidogrel and should be carefully considered during co-administration. In particular, as stated in the clopidogrel label, concomitant use with strong or moderate CYP2C19 inhibitors, such as omeprazole, should be avoided. Increased exposure and response to clopidogrel has been observed in smokers. Noteworthy, a very recent study has shown that smoking cessation in clopidogrel patients may result in reduced response and carries the risk of high on-clopidogrel platelet reactivity. Recent studies have shown clinically significant increases in exposure to CYP2C8 substrates (repaglinide, dasabuvir, and desloratadine) and a CYP2B6 substrate (s-sibutramine) following co-administration with clopidogrel, indicating that therapeutic strategies with clopidogrel should avoid these drugs.

Impact of Plasmodium vivax malaria and antimalarial treatment on cytochrome P450 activity in Brazilian patients.

To investigate the impact of Plasmodium vivax malaria and chloroquine-primaquine chemotherapy on CYP2D6 and CYP2C19 activity in patients from the Brazilian Amazon. Adult patients (n = 30) were given subtherapeutic doses of CYP2D6 and CYP2C19 phenotypic probes metoprolol (10 mg) and omeprazole (2 mg) in three different stages of vivax malaria illness: acute disease (study phase 1), post chemotherapy (phase 2) and convalescence (stage 3). Plasma concentrations of probes and CYP-hydroxylated metabolites (α-OH metoprolol and 5-OH omeprazole) were measured using LC/MS/MS. Two pharmacokinetic metrics were used to estimate CYP activity: (a) ratio of plasma concentrations of probe/metabolite at 240 minutes after administration of the probes and (b) ratio of areas under the time-concentration curves for probe/metabolite (AUC0-12h ). For statistical analysis, the pharmacokinetic metrics were normalized to the respective values in phase 3. Taqman assays were used for CYP2D6 and CYP2C19 genotyping. Cytokines levels were measured using cytometric bead array. Both pharmacokinetic metrics for metoprolol and omeprazole, and plasma concentrations of cytokines IL-6, IL-8 and IL-10 varied significantly across the three study phases (ANOVA P < 0.0001). Post hoc tests showed greater metoprolol:α-OH metoprolol ratios in phases 1 and 2 compared to phase 3, larger omeprazole:5-OH omeprazole ratios in phase 1 than in phases 2 and 3, and higher circulating IL-6, IL-8 and IL-10 in phase 1 than in phases 2 and 3. P. vivax malaria and treatment altered CYP2D6 and CYP2C19 metabolic phenotypes. CYP2C19 inhibition is attributed to a higher level of circulating proinflammatory cytokines, while suppression of CYP2D6 is ascribed mainly to chloroquine exposure.

Development of a method to determine cytochrome P450 1A2, 2C9, 2D6 and 3A4 activity sheep hepatic microsomes

IntroductionEx vivo studies of human fetal hepatic drug metabolism are uncommon as it requires access to functional liver tissue and therefore raises practical and ethical concerns. Large animal models provide an alternative opportunity to study changes in cytochrome P450 (CYP) activity in the mother and fetus during pregnancy. We aimed to develop methods to determine the activity of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in sheep hepatic microsomes. MethodsWe identified optimal conditions to determine the activity of CYP1A2 (using the probe drug phenacetin), CYP2C9 (diclofenac), CYP2D6 (dextromethorphan) and CYP3A4 (midazolam) by varying techniques for microsome extraction, probe drug concentration, incubation time and microsome concentration. The specificity of each probe drug was assessed by determining the rate of metabolism when specific CYP enzyme inhibitors were included in the reaction. ResultsThe optimum incubation time and probe drug concentration was six hours with 5 μM phenacetin (CYP1A2), four hours with 10 μM diclofenac (CYP2C9), 30 min with 1 μM of midazolam (CYP3A4) and 10 min with 1 μM dextromethorphan (CYP2D6). For both CYP2D6 and CYP3A4 reactions required 20 μg of microsomal protein, whereas for CYP1A2 and CYP2C9, reactions required 40 μg of microsomal protein. Metabolism of phenacetin, dextromethorphan and midazolam was reduced by specific enzyme inhibitors, but the specific CYP2C9 inhibitor sulfaphenazole did not substantially inhibit diclofenac metabolism. DiscussionThis study identifies the optimal conditions for determining CYP activity in maternal sheep hepatic microsomes. In doing so, we have developed a standardised protocol for assessment of microsomal activity of CYP3A4, CYP1A2 and CYP2D6, but we were unable to optimise conditions for assessment of CYP2C9. This approach can be applied to investigate the impact of pregnancy complications on maternal and fetal hepatic drug metabolism.

In Vitro Interaction of AB-FUBINACA with Human Cytochrome P450, UDP-Glucuronosyltransferase Enzymes and Drug Transporters.

AB-FUBINACA, a synthetic indazole carboxamide cannabinoid, has been used worldwide as a new psychoactive substance. Because drug abusers take various drugs concomitantly, it is necessary to explore potential AB-FUBINACA-induced drug–drug interactions caused by modulation of drug-metabolizing enzymes and transporters. In this study, the inhibitory effects of AB-FUBINACA on eight major human cytochrome P450s (CYPs) and six uridine 5′-diphospho-glucuronosyltransferases (UGTs) of human liver microsomes, and on eight clinically important transport activities including organic cation transporters (OCT)1 and OCT2, organic anion transporters (OAT)1 and OAT3, organic anion transporting polypeptide transporters (OATP)1B1 and OATP1B3, P-glycoprotein, and breast cancer resistance protein (BCRP) in transporter-overexpressing cells were investigated. AB-FUBINACA inhibited CYP2B6-mediated bupropion hydroxylation via mixed inhibition with Ki value of 15.0 µM and competitively inhibited CYP2C8-catalyzed amodiaquine N-de-ethylation, CYP2C9-catalyzed diclofenac 4′-hydroxylation, CYP2C19-catalyzed [S]-mephenytoin 4′-hydroxylation, and CYP2D6-catalyzed bufuralol 1′-hydroxylation with Ki values of 19.9, 13.1, 6.3, and 20.8 µM, respectively. AB-FUBINACA inhibited OCT2-mediated MPP+ uptake via mixed inhibition (Ki, 54.2 µM) and competitively inhibited OATP1B1-mediated estrone-3-sulfate uptake (Ki, 94.4 µM). However, AB-FUBINACA did not significantly inhibit CYP1A2, CYP2A6, CYP3A4, UGT1A1, UGT1A3, UGT1A4, UGT1A6, or UGT2B7 enzyme activities at concentrations up to 100 µM. AB-FUBINACA did not significantly inhibit the transport activities of OCT1, OAT1/3, OATP1B3, P-glycoprotein, or BCRP at concentrations up to 250 μM. As the pharmacokinetics of AB-FUBINACA in humans and animals remain unknown, it is necessary to clinically evaluate potential in vivo pharmacokinetic drug–drug interactions induced by AB-FUBINACA-mediated inhibition of CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, OCT2, and OATP1B1 activities.

Main contribution of UGT1A1 and CYP2C9 in the metabolism of UR-1102, a novel agent for the treatment of gout

UR-1102, a novel uricosuric agent for treating gout, has been confirmed to exhibit a pharmacological effect in patients. We clarified its metabolic pathway, estimated the contribution of each metabolic enzyme, and assessed the impact of genetic polymorphisms using human in vitro materials. Glucuronide, sulfate and oxidative metabolites of UR-1102 were detected in human hepatocytes. The intrinsic clearance by glucuronidation or oxidation in human liver microsomes was comparable, but sulfation in the cytosol was much lower, indicating that the rank order of contribution was glucuronidation ≥ oxidation > sulfation. Recombinant UGT1A1 and UGT1A3 showed high glucuronidation of UR-1102. We took advantage of a difference in the inhibitory sensitivity of atazanavir to the UGT isoforms and estimated the fraction metabolised (fm) with UGT1A1 to be 70%. Studies using recombinant CYPs and CYP isoform-specific inhibitors showed that oxidation was mediated exclusively by CYP2C9. The effect of UGT1A1 and CYP2C9 inhibitors on UR-1102 metabolism in hepatocytes did not differ markedly between the wild type and variants.

Abstract 3016: Tucatinib inhibits CYP3A, CYP2C8 and P-gp-mediated elimination and is impacted by CYP2C8 inhibition in healthy volunteers

Abstract Background: Tucatinib is a potent, highly selective HER2 tyrosine kinase inhibitor in development for the treatment of patients with HER2+ metastatic breast cancer. In vitro metabolism studies suggest that drug metabolizing enzymes CYP2C8 and CYP3A play a role in tucatinib metabolism. Tucatinib exhibits competitive inhibition of CYP2C8, CYP2C9, CYP3A, and P-gp, and metabolism-dependent inactivation of CYP3A in vitro. ONT-380-012 was a clinical drug interaction study conducted to evaluate the magnitude of potential enzyme and transporter interactions for tucatinib (both as a victim and perpetrator), and the safety of healthy subjects when administered tucatinib doses at therapeutic levels (300 mg BID). Methods: Healthy volunteers (n=116) at multiple centers were enrolled in the study. Parts A-C evaluated the effects of a strong CYP2C8 inhibitor (gemfibrozil), a strong CYP3A inhibitor (itraconazole), and a CYP3A/CYP2C8 inducer (rifampin) on single-dose tucatinib (300 mg) PK. Parts D and E assessed the effects of steady-state tucatinib (300 mg BID) on single-dose PK of substrate probes for CYP2C8 (repaglinide), CYP2C9 (tolbutamide), CYP3A (midazolam), and P-gp (digoxin). Plasma samples were collected for PK analysis and drug concentrations were measured using validated LC-MS/MS methods. Results: A strong CYP3A inhibitor (itraconazole) increased tucatinib AUCinf and Cmax 1.3-fold. A CYP3A/CYP2C8 inducer (rifampin) decreased tucatinib AUCinf and Cmax 48% and 37%, respectively. A strong CYP2C8 inhibitor (gemfibrozil) increased tucatinib AUCinf and Cmax 3.1- and 1.6-fold, respectively. Tucatinib increased the AUCinf and Cmax of the CYP3A substrate (midazolam) 5.7- and 3.0-fold, respectively, the AUCinf and Cmax of the CYP2C8 substrate (repaglinide) 1.7-fold, and the AUCinf of the P-gp substrate (digoxin) 1.5-fold. Tucatinib had no impact on the PK of the CYP2C9 substrate (tolbutamide). Overall, tucatinib was well tolerated in healthy volunteers when administered 300 mg BID. Conclusions: Together, these data indicate tucatinib is metabolized primarily by CYP2C8 and to a lesser extent via CYP3A. Tucatinib was found to be a strong inhibitor of CYP3A, a weak inhibitor of CYP2C8 and P-gp, and had no impact on CYP2C9-mediated metabolism in vivo. Citation Format: Ariel R. Topletz-Erickson, Anthony Lee, Hao Sun, JoAl Mayor, Luke Walker, Christopher J. Endres. Tucatinib inhibits CYP3A, CYP2C8 and P-gp-mediated elimination and is impacted by CYP2C8 inhibition in healthy volunteers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3016.

Effect of High-Dose Esomeprazole on CYP1A2, CYP2C19, and CYP3A4 Activities in Humans: Evidence for Substantial and Long-lasting Inhibition of CYP2C19.

In vitro, esomeprazole is a time-dependent inhibitor of CYP2C19. Additionally, racemic omeprazole induces CYP1A2 and omeprazole and its metabolites inhibit CYP3A4 in vitro. In this 5-phase study, 10 healthy volunteers ingested 20mg pantoprazole, 0.5mg midazolam, and 50mg caffeine as respective index substrates for CYP2C19, 3A4, and 1A2 before and 1, 25, 49 (pantoprazole only), and 73hours after an 8-day pretreatment with 80mg esomeprazole twice daily. The area under the plasma concentration-time curve (AUC) of R-pantoprazole increased 4.92-fold (90% confidence interval (CI) 3.55-6.82), 2.31-fold (90% CI 1.85-2.88), and 1.33-fold (90% CI 1.06-1.68) at the 1-hour, 25-hour, and 73-hour phases, respectively, consistent with a substantial and persistent inhibition of CYP2C19. The AUC of midazolam increased up to 1.44-fold (90% CI 1.22-1.72) and the paraxanthine/caffeine metabolic ratio up to 1.19-fold (90% CI 1.04-1.36), when the index substrates were taken 1hour after esomeprazole. Based on the recovery of R-pantoprazole oral clearance, the turnover half-life of CYP2C19 was estimated to average 53hours. Pharmacokinetic simulation based on the observed concentrations of esomeprazole and its metabolites as well as their published CYP2C19 inhibitory constants was well in line with the observed changes in R-pantoprazole pharmacokinetics during the course of the study. Extrapolations assuming linear pharmacokinetics of esomeprazole suggested weak to moderate inhibition at 20 and 40mg twice daily dosing. In conclusion, high-dose esomeprazole can cause strong inhibition of CYP2C19, but only weakly inhibits CYP3A4 and leads to minor induction of CYP1A2. The enzymatic activity of CYP2C19 recovers gradually in ~3-4days after discontinuation of esomeprazole treatment.

Computational Modeling and Pharmacokinetics/ADMET Study of Some Arylpiperazine Derivatives as Novel Antipsychotic Agents Targeting Depression

This study focuses on Quantitative structure–activity relationship (QSAR) and in silico pharmacokinetics/ADMET predictions to investigate the structural features and pharmacokinetic/ADMET properties that influenced the antipsychotic activity of some arylpiperazine derivatives as inhibitors of Serotonin Transporter (SERT) for antidepressant agents. Density Functional Theory approach (DFT/B3LYP/6-31G*) via Spartan 14 V1.1.4 software was used for the geometry optimization of the compounds while the Genetic Function Algorithm (GFA) and Multiple Linear Regression Analysis (MLRA) in Material studio software were used for variable selection and development of QSAR models. The statistical analysis and validation parameters of the best model (RTrain2 = 0.944, RTest2 = 0.637, Qcv2 = 0.895, cRp2 = 0.845 and RMSE = 0.100) shows that the model was predictive, reliable, robust and very stable. More so, molecular descriptors; SpMax6_Bhm, VP-3, geomDiameter, RDF35i and E1e were significantly contributed to the observed antipsychotic activities of the compounds with SpMax6_Bhm (37.5%) played a predominant role and positively correlated to the observed antipsychotic property of the compounds. Similarly, the in silico pharmacokinetics/ADMET investigations revealed that the selected compounds portend to be orally bioavailable, highly absorbed by the gastrointestinal system and could permeate into the brain with low ADMET risk. Likewise, all the selected compounds were inhibitors of CYP2C19 and CYP2D6 cytochromes P450 (CYP) enzymes and none of the selected compounds exhibit human ether-a-go-go-related gene (hERG) cardiovascular toxicity. Hence, the model possessed good quality assurance and satisfied OECD Principles for model development. In consequence, the physicochemical and pharmacokinetic parameters/properties derived from this study could be considered when developing other arylpiperazine derivatives with improved activity as antidepressant agents.

Molecular docking, PKPD, and assessment of toxicity of few chalcone analogues as EGFR inhibitor in search of anticancer agents

In the present work, molecular docking of the chalcone analogues with receptor EGFR carried out using erlotinib as reference drug is reported. About 15 chalcone analogues were analyzed CHL(1–15). Molecules CHL2, CHL3, CHL9, CHL11, and CHL15 found strong affinity for receptor EGFR exhibiting binding energies − 7.7 kcal/mol, − 7.5 kcal/mol, − 7.6 kcal/mol, − 7.9 kcal/mol, and − 8.1 kcal/mol, respectively, when erlotinib a reference drug exhibits binding energy − 7.6 kcal/mol. Toxicity for molecules was assessed against the cytochromes P450 (CYP) and P-gp using Swiss ADMET. Molecule CHL9 could be a suitable lead compound inhibitor to CYP1A2 followed by CHL2 inhibitor of CYP1A2 and CYP2C9 and CHL15 with a most stable binding affinity of − 8.1 kcal/mol, inhibiting CYP1A2, CYP2C19, and CYP2D6. CHL3 has a binding affinity of − 7.5 kcal/mol, inhibiting all the 05 CYP enzymes (CYP1A2, CYP2C19, CYP2C9, CYP2D6, and CYP3A4). CHL11 has a binding affinity of − 7.9 kcal/mol, inhibiting CYP1A2, CYP2C19, and CYP2C9. Considering inhibition of CYP family enzymes by molecules, further here we have perform the enrichment analysis to these CYP family enzymes and reported the metabolic pathways which were probably affected by inhibition of these enzymes using EnrichR online enrichment analysis server. The current predictions over these 15 chalcone derivatives will be needed to further investigate in vivo and in vitro conditions to identify the optimum therapeutic efficacy and least toxicity.

Cytochrome-P450-Mediated Drug-Drug Interactions of Substrate Drugs: Assessing Clinical Risk Based on Molecular Properties and an Extended Clearance Classification System.

Cytochrome-P450 (P450) isoforms are major drug-metabolizing enzymes implicated in the clearance and drug-drug interactions (DDIs) of diverse small-molecule drugs. Here, we evaluated the association between primary physicochemical descriptors of substrate drugs and their clinical DDI risk with P450 index (probe) inhibitors using an exhaustive clinical data set (n = 397, substrate-inhibitor pairs). Additionally, the ability of extended clearance classification system (ECCS), a categorical clearance mechanism model, to predict P450 DDI risk was assessed. The clinical data set indicated that basic and neutral compounds are probable candidates to show a higher magnitude of DDIs on P450 inhibition (i.e., plasma exposure change > twofold). Additionally, trends with lipophilicity were apparent for P450-based DDIs. ECCS class 2 drugs (high-permeability bases/neutrals) have higher probability to show moderate-to-strong DDIs with probe inhibitors of CYP1A2/2C19/2C9/2D6/3A, while ECCS class 1A/1B drugs are prone to interactions with inhibitors of CYP2C8 and CYP2C9. On the other hand, P450-based DDIs are notably small for classes 3A/3B/4. In conclusion, this study emphasizes the relevance of the ECCS framework in clearance characterization to evaluate victim DDI liabilities and aid chemists in mitigating risk during drug design.

Modulation of Major Human Liver Microsomal Cytochromes P450 by Component Alkaloids of Goldenseal: Time-Dependent Inhibition and Allosteric Effects.

Botanical and other natural products (NPs) are often coconsumed with prescription medications, presenting a risk for cytochrome P450 (P450)-mediated NP-drug interactions. The NP goldenseal (Hydrastis canadensis) has exhibited antimicrobial activities in vitro attributed to isoquinoline alkaloids contained in the plant, primarily berberine, (-)-β-hydrastine, and to a lesser extent, hydrastinine. These alkaloids contain methylenedioxyphenyl rings, structural alerts with potential to inactivate P450s through formation of metabolic intermediate complexes. Time-dependent inhibition experiments were conducted to evaluate their ability to inhibit major P450 activities in human liver microsomes by using a cocktail of isozyme-specific substrate probes. Berberine inhibited CYP2D6 (dextromethorphan O-demethylation; K I = 2.7 μM, kinact = 0.065 minute-1) and CYP3A4/5 (midazolam 1'-hydroxylation; K I = 14.8 μM, kinact = 0.019 minute-1); (-)-β-hydrastine inhibited CYP2C9 (diclofenac 4'-hydroxylation; K I = 49 μM, kinact = 0.036 minute-1), CYP2D6 (K I > 250 μM, kinact > 0.06 minute-1), and CYP3A4/5 (K I = 28 μM, kinact = 0.056 minute-1); and hydrastinine inhibited CYP2D6 (K I = 37 μM, kinact = 0.049 minute-1) activity. Berberine additionally exhibited allosteric effects on midazolam hydroxylation, showing both positive and negative heterotropic cooperativity. Experiments with recombinant isozymes showed that berberine activated midazolam 1'-hydroxylation by CYP3A5, lowering K m(app), but showed mixed inhibition and negative cooperativity toward this reaction when catalyzed by CYP3A4. Berberine inactivated CYP3A4 at a much faster rate than CYP3A5 and was a noncompetitive inhibitor of midazolam 4-hydroxylation by CYP3A4 but a strong mixed inhibitor of the CYP3A5 catalyzed reaction. These complex kinetics should be considered when extrapolating the risk for NP-drug interactions involving goldenseal. SIGNIFICANCE STATEMENT: Robust kinetic parameters were determined for the reversible and time-dependent inhibition of CYP2C9, CYP2D6, and CYP3A4/5 activities in human liver microsomes by major component isoquinoline alkaloids contained in the botanical natural product goldenseal. The alkaloid berberine also exhibited opposing, isozyme-specific allosteric effects on midazolam hydroxylation mediated by recombinant CYP3A4 (inhibition) and CYP3A5 (activation). These data will inform the development of a physiologically based pharmacokinetic model that can be used to predict potential clinically relevant goldenseal-drug interactions.