scholarly journals Isoniazid Mediates theCYP2B6*6Genotype-Dependent Interaction between Efavirenz and Antituberculosis Drug Therapy through Mechanism-Based Inactivation of CYP2A6

2014 ◽  
Vol 58 (7) ◽  
pp. 4145-4152 ◽  
Author(s):  
Michael H. Court ◽  
Fawziah E. Almutairi ◽  
David J. Greenblatt ◽  
Suwagmani Hazarika ◽  
Hongyan Sheng ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Plasma Concentrations ◽  
Liver Microsomes ◽  
Selective Inhibition ◽  
Recombinant Enzymes ◽  
Antituberculosis Drugs ◽  
Antituberculosis Therapy ◽  
Dependent Inhibition ◽  
Drug Drug Interaction

ABSTRACTEfavirenz is commonly used to treat patients coinfected with human immunodeficiency virus and tuberculosis. Previous clinical studies have observed paradoxically elevated efavirenz plasma concentrations in patients with theCYP2B6*6/*6genotype (but not theCYP2B6*1/*1genotype) during coadministration with the commonly used four-drug antituberculosis therapy. This study sought to elucidate the mechanism underlying this genotype-dependent drug-drug interaction.In vitrostudies were conducted to determine whether one or more of the antituberculosis drugs (rifampin, isoniazid, pyrazinamide, or ethambutol) potently inhibit efavirenz 8-hydroxylation by CYP2B6 or efavirenz 7-hydroxylation by CYP2A6, the main mechanisms of efavirenz clearance. Time- and concentration-dependent kinetics of inhibition by the antituberculosis drugs were determined using genotyped human liver microsomes (HLMs) and recombinant CYP2A6, CYP2B6.1, and CYP2B6.6 enzymes. Although none of the antituberculosis drugs evaluated at up to 10 times clinical plasma concentrations were found to inhibit efavirenz 8-hydroxylation by HLMs, both rifampin (apparent inhibition constant [Ki] = 368 μM) and pyrazinamide (Ki= 637 μM) showed relatively weak inhibition of efavirenz 7-hydroxylation. Importantly, isoniazid demonstrated potent time-dependent inhibition of efavirenz 7-hydroxylation in both HLMs (inhibitor concentration required for half-maximal inactivation [KI] = 30 μM; maximal rate constant of inactivation [kinact] = 0.023 min−1) and recombinant CYP2A6 (KI= 15 μM;kinact= 0.024 min−1) and also formed a metabolite intermediate complex consistent with mechanism-based inhibition. Selective inhibition of the CYP2B6.6 allozyme could not be demonstrated for any of the antituberculosis drugs using either recombinant enzymes orCYP2B6*6genotype HLMs. In conclusion, the results of this study identify isoniazid as the most likely perpetrator of this clinically important drug-drug interaction through mechanism-based inactivation of CYP2A6.

scholarly journals In vitro study on the effect of cornin on the activity of cytochrome P450 enzymes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qun Zhang ◽  
Zengqiang Qu ◽  
Yanqing Zhou ◽  
Jin Zhou ◽  
Junwei Yang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Interaction ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Cytochrome P450 Enzymes ◽  
Drug Drug Interaction ◽  
Dose Dependent

Abstract Background Cornin is a commonly used herb in cardiology for its cardioprotective effect. The effect of herbs on the activity of cytochrome P450 enzymes (CYP450s) can induce adverse drug-drug interaction even treatment failure. Therefore, it is necessary to investigate the effect of cornin on the activity of CYP450s, which can provide more guidance for the clinical application of cornin. Methods Cornin (100 μM) was incubated with eight isoforms of CYP450s, including CYP1A2, 2A6, 3A4, 2C8, 2C9, 2C19, 2D6, and 2E1, in pooled human liver microsomes. The inhibition model and corresponding parameters were also investigated. Results Cornin exerted significant inhibitory effect on the activity of CYP3A4, 2C9, and 2E1 in a dose-dependent manner with the IC50 values of 9.20, 22.91, and 14.28 μM, respectively (p < 0.05). Cornin inhibited the activity of CYP3A4 non-competitively with the Ki value of 4.69 μM, while the inhibition of CYP2C9 and 2E1 by cornin was competitive with the Ki value of 11.31 and 6.54 μM, respectively. Additionally, the inhibition of CYP3A4 by cornin was found to be time-dependent with the KI/Kinact value of 6.40/0.055 min− 1·μM− 1. Conclusions The inhibitory effect of cornin on the activity of CYP3A4, 2C9, and 2E1 indicated the potential drug-drug interaction between cornin and drugs metabolized by these CYP450s, which needs further investigation and validation.

scholarly journals Preclinical evaluation of strasseriolides A–D, potent antiplasmodial macrolides isolated from Strasseria geniculata CF-247,251

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Frederick Annang ◽  
Guiomar Pérez-Moreno ◽  
Caridad Díaz ◽  
Victor González-Menéndez ◽  
Nuria de Pedro Montejo ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Liver Microsomes ◽  
In Vivo Studies ◽  
Significant Activity ◽  
In Vivo Efficacy ◽  
Preclinical Evaluation ◽  
Drug Drug Interaction ◽  
Further Development

Abstract Background Malaria is a global health problem for which novel therapeutic compounds are needed. To this end, a recently published novel family of antiplasmodial macrolides, strasseriolides A–D, was herein subjected to in vivo efficacy studies and preclinical evaluation in order to identify the most promising candidate(s) for further development. Methods Preclinical evaluation of strasseriolides A–D was performed by MTT-based cytotoxicity assay in THLE-2 (CRL-2706) liver cells, cardiotoxicity screening using the FluxOR™ potassium assay in hERG expressed HEK cells, LC–MS-based analysis of drug-drug interaction involving CYP3A4, CYP2D6 and CYP2C9 isoforms inhibition and metabolic stability assays in human liver microsomes. Mice in vivo toxicity studies were also accomplished by i.v. administration of the compounds (vehicle: 0.5% HPMC, 0.5% Tween 80, 0.5% Benzyl alcohol) in mice at 25 mg/kg dosage. Plasma were prepared from mice blood samples obtained at different time points (over a 24-h period), and analysed by LC-MS to quantify compounds. The most promising compounds, strasseriolides C and D, were subjected to a preliminary in vivo efficacy study in which transgenic GFP-luciferase expressing Plasmodium berghei strain ANKA-infected Swiss Webster female mice (n = 4–5) were treated 48 h post-infection with an i.p. dosage of strasseriolide C at 50 mg/kg and strasseriolide D at 22 mg/kg for four days after which luciferase activity was quantified on day 5 in an IVIS® Lumina II imager. Results Strasseriolides A–D showed no cytotoxicity, no carditoxicity and no drug-drug interaction problems in vitro with varying intrinsic clearance (CLint). Only strasseriolide B was highly toxic to mice in vivo (even at 1 mg/kg i.v. dosage) and, therefore, discontinued in further in vivo studies. Strasseriolide D showed statistically significant activity in vivo giving rise to lower parasitaemia levels (70% lower) compared to the controls treated with vehicle. Conclusions Animal efficacy and preclinical evaluation of the recently discovered potent antiplasmodial macrolides, strasseriolides A–D, led to the identification of strasseriolide D as the most promising compound for further development. Future studies dealing on structure optimization, formulation and establishment of optimal in vivo dosage explorations of this novel compound class could enhance their clinical potency and allow for progress to later stages of the developmental pipeline.

Inhibitory Effect of Citalopram on the Pharmacokinetics of Carvedilol in Rats and in vitro Models

Pharmacology ◽  
2017 ◽  
Vol 100 (5-6) ◽  
pp. 301-307
Author(s):  
Maria Bianca Abrudan ◽  
Dana Maria Muntean ◽  
Daniela Saveta Popa ◽  
Ana-Maria Gheldiu ◽  
Maria Adriana Neag ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Plasma Concentration ◽  
Metabolic Rate ◽  
Liver Microsome ◽  
Peak Plasma ◽  
Peak Plasma Concentration ◽  
Femoral Vein ◽  
Plasma Concentrations ◽  
Drug Drug Interaction

Background/Aims: The aim of this study was to investigate the drug-drug interaction between carvedilol and citalopram based on carvedilol metabolism in vitro and his pharmacokinetics (PKs) in vivo after the oral administration of the single drug and both drugs, and reveal citalopram effects on the PKs of carvedilol. Methods: Each rat was cannulated on the femoral vein, prior to being connected to BASi Culex ABC®. Carvedilol was orally administrated in rats (3.57 mg/kg body weight [b.w.]) in the absence of citalopram or after a pre-treatment with multiple oral doses of citalopram (1.42 mg/kg b.w.). Plasma concentrations of carvedilol were determined using high-performance liquid chromatography-MS at the designated time points after drug administration, and the main PK parameters were calculated by noncompartmental analysis. In addition, effects of citalopram on the metabolic rate of carvedilol were investigated using rat-pooled liver microsome incubation systems. Results: During co-administration, significant increases of the area under the plasma concentration-time curve as well as of the peak plasma concentration were observed. The rat-pooled liver microsome incubation experiment indicated that citalopram could decrease the metabolic rate of carvedilol. Conclusion: Citalopram co-administration led to a significant alteration of carvedilol's PK profile in rats; it also demonstrated, in vitro, these effects could be explained by the existence of a drug-drug interaction mediated by CYP2D6 inhibition.

Pharmacokinetic Drug-drug Interaction of Antibiotics Used in Sepsis Care in China

2020 ◽  
Vol 21 ◽  
Author(s):  
Xuan Yu ◽  
Zixuan Chu ◽  
Jian Li ◽  
Rongrong He ◽  
Yaya Wang ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Drug Interactions ◽  
Penicillin G ◽  
Literature Mining ◽  
Human Pharmacokinetics ◽  
P450 Enzyme ◽  
Drug Drug Interaction ◽  
Pharmacokinetic Drug ◽  
Sepsis Care

Background: Many antibiotics have a high potential for having an interaction with drugs, as perpetrator and/or victim, in critically ill patients, and particularly in sepsis patients. Methods: The aim of this review is to summarize the pharmacokinetic drug-drug interaction (DDI) of 45 antibiotics commonly used in sepsis care in China. Literature mining was conducted to obtain human pharmacokinetics/dispositions of the antibiotics, their interactions with drug metabolizing enzymes or transporters, and their associated clinical drug interactions. Potential DDI is indicated by a DDI index > 0.1 for inhibition or a treated-cell/untreated-cell ratio of enzyme activity being > 2 for induction. Results: The literature-mined information on human pharmacokinetics of the identified antibiotics and their potential drug interactions is summarized. Conclusion: Antibiotic-perpetrated drug interactions, involving P450 enzyme inhibition, have been reported for four lipophilic antibacterials (ciprofloxacin, erythromycin, trimethoprim, and trimethoprim-sulfamethoxazole) and three lipophilic antifungals (fluconazole, itraconazole, and voriconazole). In addition, seven hydrophilic antibacterials (ceftriaxone, cefamandole, piperacillin, penicillin G, amikacin, metronidazole, and linezolid) inhibit drug transporters in vitro. Despite no reported clinical PK drug interactions with the transporters, caution is advised in the use of these antibacterials. Eight hydrophilic antibacterials (all β-lactams; meropenem, cefotaxime, cefazolin, piperacillin, ticarcillin, penicillin G, ampicillin, and flucloxacillin), are potential victims of drug interactions due to transporter inhibition. Rifampin is reported to perpetrate drug interactions by inducing CYP3A or inhibiting OATP1B; it is also reported to be a victim of drug interactions, due to the dual inhibition of CYP3A4 and OATP1B by indinavir. In addition, three antifungals (caspofungin, itraconazole, and voriconazole) are reported to be victims of drug interactions because of P450 enzyme induction. Reports for other antibiotics acting as victims in drug interactions are scarce.

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