Impact of Nonspecific Binding to Microsomes and Phospholipid on the Inhibition of Cytochrome P4502D6: Implications for Relating in Vitro Inhibition Data to in Vivo Drug Interactions

Margolis, Jeannine M.; Obach, R. Scott

doi:10.1124/dmd.31.5.606

Cited by 128 publications

(80 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Overprediction of drug-drug interactions has been reported for CYP3A4 inactivation by various kinase inhibitors (Kenny et al, 2012). For experimentally determined kinetic parameters (such as K i ), nonspecific binding and albumin tend to decrease "effective concentrations" of some drugs and lead to overestimation of parameters obtained from HLM incubations (Margolis and Obach 2003;Wattanachai et al, 2011;Nagar and Korzekwa 2012). The decreased inhibitory potency due to overestimation of K i values may result in underprediction of drug-drug interaction potential, a phenomenon was not seen during our analysis.…”

Section: Discussionmentioning

confidence: 51%

Pathway-Dependent Inhibition of Paclitaxel Hydroxylation by Kinase Inhibitors and Assessment of Drug–Drug Interaction Potentials

Wang

Pan

et al. 2014

Drug Metab Dispos

View full text Add to dashboard Cite

Paclitaxel is often used in combination with small molecule kinase inhibitors to enhance antitumor efficacy against various malignancies. Because paclitaxel is metabolized by CYP2C8 and CYP3A4, the possibility of drug-drug interactions mediated by enzyme inhibition may exist between the combining agents. In the present study, a total of 12 kinase inhibitors were evaluated for inhibitory potency in human liver microsomes by monitoring the formation of CYP2C8 and CYP3A4 metabolites simultaneously. For reversible inhibition, nilotinib was found to be the most potent inhibitor against both CYP2C8 and CYP3A4, and the inhibition potency could be explained by strong hydrogen binding based on molecular docking simulations and type II binding based on spectral analysis. Comparison of K i values revealed that the CYP2C8 pathway was more sensitive toward some kinase inhibitors (such as axitinib), while the CYP3A4 pathway was preferentially inhibited by others (such as bosutinib). Pathwaydependent inactivation (time-dependent inhibition) was also observed for a number of kinase inhibitors against CYP3A4 but not CYP2C8. Further studies showed that axitinib had a K I of 0.93 mM and k inact of 0.0137 min 21 , and the observed inactivation toward CYP3A4 was probably due to the formation of reactive intermediate (s). Using a static model, a reasonably accurate prediction of drug-drug interactions was achieved by incorporating parallel pathways and hepatic extraction ratio. The present results suggest that potent and pathway-dependent inhibition of CYP2C8 and/or CYP3A4 pathways by kinase inhibitors may alter the ratio of paclitaxel metabolites in vivo, and that such changes can be clinically relevant as differential metabolism has been linked to paclitaxel-induced neurotoxicity in cancer patients.

show abstract

Section: Discussionmentioning

confidence: 51%

Pathway-Dependent Inhibition of Paclitaxel Hydroxylation by Kinase Inhibitors and Assessment of Drug–Drug Interaction Potentials

Wang

Pan

et al. 2014

Drug Metab Dispos

View full text Add to dashboard Cite

show abstract

“…The k inact and K I values for racemic fluoxetine agree well with the k inact and apparent K I values of 0.03 minϪ1 and 8 M reported by McGinnity et al (2006), respectively. Values were not corrected for nonspecific binding, which can be substantial for fluoxetine (Margolis and Obach, 2003). Correcting for unbound fluoxetine, the estimates of K I values would be [10-fold lower (McGinnity et al, 2006)] and are within steady-state total plasma levels of fluoxetine (ranging from 0.15 to 1.5 M) found after therapeutic dosing of fluoxetine (Orsulak et al, 1988).…”

Section: Resultsmentioning

confidence: 99%

Differential Time- and NADPH-Dependent Inhibition of CYP2C19 by Enantiomers of Fluoxetine

Stresser

Mason²,

Perloff³

et al. 2009

Drug Metab Dispos

View full text Add to dashboard Cite

] is a widely used selective serotonin reuptake inhibitor, with more than 23 million prescriptions filled for the generic drug within the United States in 2006 (http://www.drugtopics.com/Topϩ200ϩ Drugs). Racemic fluoxetine and its (R)-and (S)-enantiomers are metabolized by N-demethylation to the pharmacologically active metabolite norfluoxetine by CYP2D6 and other cytochrome P450 (P450) isoforms (Margolis et al., 2000;Mandrioli et al., 2006; refer to latter for chemical structure). Fluoxetine also undergoes CYP2C19-mediated O-dealkylation to the p-trifluoromethylphenol metabolite (Liu et al., 2002). In addition, racemic fluoxetine and/or its enantiomers have been shown to be reversible inhibitors of CYP2D6 (Brosen and Skjelbo, 1991;Stevens and Wrighton, 1993), CYP2C19 (Kobayashi et al., 1995;Foti and Wahlstrom, 2008), CYP3A4 (von Moltke et al., 1994;Ring et al., 1995), and CYP2C9 (Schmider et al., 1997;Hemeryck et al., 1999). Fewer studies have been conducted examining the potential for fluoxetine to be a mechanism-based inhibitor of P450. Mayhew et al. (2000) showed fluoxetine to be a mechanism-based inhibitor of CYP3A4, and McGinnity et al. (2006) recently demonstrated time-and concentration-dependent inhibition of CYP3A4 and also CYP2C19 in multiple in vitro systems, including hepatocytes. With heightened awareness of links between mechanism-based inhibitors, covalent binding and idiosyncratic toxicity (Ulrich, 2007), as well as the appearance of regulatory guidance for drugdrug interaction testing (U.S. Food and Drug Administration, http:// www.fda.gov/cber/gdlns/interactstud.htm.), many laboratories are establishing or revisiting their procedures for conducting time-dependent P450 inhibition testing. In the process of augmenting our laboratory's CYP2C19 time-dependent inhibition assay, we tested model compounds intended to serve as reference inhibitors. In many laboratories, ticlopidine is used as a positive control inhibitor in this assay (Ha-Duong et al., 2001), but we and others have found it to be only weakly inhibitory (Stresser et al., 2008), and it is therefore unsatisfactory as a potent acting benchmark. In this report, we confirm the findings of McGinnity et al. (2006) with racemic fluoxetine and show that the enantiomers of fluoxetine are effective, but kinetically different, time-dependent inhibitors of CYP2C19. Materials and MethodsMaterials. Pooled human liver microsomes (HLM), S-benzylnirvanol, (S)-mephenytoin, (Ϯ)4Ј-OH-mephenytoin, and stable-isotope-labeled (Ϯ)4Ј-hydroxy mephenytoin-D3, were obtained from BD Biosciences (Woburn, MA). All other chemicals, including (Ϯ)-fluoxetine, (R)-fluoxetine, (S)-fluoxetine, (Ϯ)-norfluoxetine, and ticlopidine were obtained from Sigma-Aldrich (St. Louis, MO).S-Mephenytoin 4-Hydroxylase IC 50 Shift Assays. Inhibition by test chemicals was determined using seven concentrations of inhibitor, separated by 0.5 log spacing, in a final volume 0.4 ml. Reactions contained 40 M S-mephenytoin (approximately the K M ), 0.3 mg/ml of pooled HLM, 1.3 mM NADPϩ, 3.3 mM gl...

show abstract

“…14) After a 5-min incubation at 37°C, the mixture was centrifuged at 105000 g for 60 min at 4°C, 13) and the concentration of nilvadipine in the supernatant was measured by HPLC with an analytical column Inertsil ODS-3 (150ϫ4.6 mm I.D., GL Sciences Inc., Tokyo, Japan). The column temperature was set at 40°C.…”

Section: Determination Of Free Fraction In Incubation Mixturementioning

confidence: 99%

“…Recent studies have been shown that inhibition constants (K i ) for drugs as inhibitors of microsomal drug-metabolizing enzymes, such as CYP, should be correlated for the extent of nonspecific binding to components of the in vitro matrix, by measurement of the unbound fraction under the incubation condition, to yield more accurate determination of the constant. 13) However, there are few such detailed studies on the effect of nilvadipine on human hepatic CYP-mediated drugmetabolizing activity.…”

mentioning

confidence: 99%

Effect of Nilvadipine, a Dihydropyridine Calcium Antagonist, on Cytochrome P450 Activities in Human Hepatic Microsomes

Niwa

Shiraga

Hashimoto

et al. 2004

Biological & Pharmaceutical Bulletin

View full text Add to dashboard Cite

Impact of Nonspecific Binding to Microsomes and Phospholipid on the Inhibition of Cytochrome P4502D6: Implications for Relating in Vitro Inhibition Data to in Vivo Drug Interactions

Cited by 128 publications

References 14 publications

Pathway-Dependent Inhibition of Paclitaxel Hydroxylation by Kinase Inhibitors and Assessment of Drug–Drug Interaction Potentials

Pathway-Dependent Inhibition of Paclitaxel Hydroxylation by Kinase Inhibitors and Assessment of Drug–Drug Interaction Potentials

Differential Time- and NADPH-Dependent Inhibition of CYP2C19 by Enantiomers of Fluoxetine

Effect of Nilvadipine, a Dihydropyridine Calcium Antagonist, on Cytochrome P450 Activities in Human Hepatic Microsomes

Contact Info

Product

Resources

About