Modulation of midazolam 1-hydroxylation activity in vitro by neurotransmitters and precursors

Martı́nez, Carmen; Gervasini, Guillermo; Agúndez, José A. G.; Carrillo, Juan Antonio Cabrera; Ramos, Sara I.; Garcia-Gamito, F.J.; Gallardo, Lourdes; Benı́tez, Julio

doi:10.1007/s002280050733

Cited by 16 publications

(16 citation statements)

References 29 publications

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“…Therefore, we investigated the impact of VU0448187 on the binding affinity (K m ) and catalytic efficiency (V max ) of MDZ 1-hydroxylation in recombinant CYP3A4 and CYP3A5 (with and without cytochrome b 5 ), as well as in human liver microsomes. Not surprisingly, the kinetics of MDZ metabolism (1-OH-MDZ formation) was linear at concentrations up to, but not exceeding, 10 mM; as expected, we observed substrate-inhibition kinetics at higher concentrations (100 mM) (Martínez et al, 2000;Lin et al, 2001; Khan et al, 2002). Consistent with previous accounts of Fig.…”

Section: Resultssupporting

confidence: 92%

“…2) equations and represented as nanomoles per minute per milligram of protein (human liver microsomes) or picomoles per minute per picomole of P450 (CYP3A4 or CYP3A5). Because MDZ metabolism undergoes substrate inhibition at higher concentrations (Martínez et al, 2000;Khan et al, 2002), it was decided to report all data using Eq. 2 for completeness.…”

Section: Methodsmentioning

confidence: 99%

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Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu₅: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions

et al. 2013

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Allosteric modulation of G protein-coupled receptors has gained considerable attention in the drug discovery arena because it opens avenues to achieve greater selectivity over orthosteric ligands. We recently identified a series of positive allosteric modulators (PAMs) of metabotropic glutamate receptor 5 (mGlu 5 ) for the treatment of schizophrenia that exhibited robust heterotropic activation of CYP3A4 enzymatic activity. The prototypical compound from this series, 5-(4-fluorobenzyl)-2-((3-fluorophenoxy)methyl)-4,5,6,7-tetrahydropyrazolo[1, 5-a]pyrazine (VU0448187), was found to activate CYP3A4 to >100% of its baseline intrinsic midazolam (MDZ) hydroxylase activity in vitro; activation was CYP3A substrate specific and mGlu 5 PAM dependent. Additional studies revealed the concentration-dependence of CYP3A activation by VU0448187 in multispecies hepatic and intestinal microsomes and hepatocytes, as well as a diminished effect observed in the presence of ketoconazole. Kinetic analyses of the effect of VU0448187 on MDZ metabolism in recombinant P450 or human liver microsomes resulted in a significant increase in V max (minimal change in K m ) and required the presence of cytochrome b 5 . The atypical kinetics translated in vivo, as rats receiving an intraperitoneal administration of VU0448187 prior to MDZ treatment demonstrated a significant increase in circulating 1-and 4-hydroxy-midazolam (1-OH-MDZ, 4-OH-MDZ) levels compared with rats administered MDZ alone. The discovery of a potent substrate-selective activator of rodent CYP3A with an in vitro to in vivo translation serves to illuminate the impact of increasing intrinsic enzymatic activity of hepatic and extrahepatic CYP3A in rodents, and presents the basis to build models capable of framing the clinical relevance of substrate-dependent heterotropic activation.

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Section: Resultssupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu₅: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions

et al. 2013

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“…K m values for midazolam 1Ј-hydroxylase were 2.27 Ϯ 0.18, 0.622 Ϯ 0.025, and 1.53 Ϯ 0.09 M in HLM, rCYP3A4, and rCYP3A5, respectively (Table 7; Fig. 2), consistent with previously reported values of 2.4 to 12 M for liver microsomes (Gascon and Dayer, 1991;Sharer et al, 1995;Ghosal et al, 1996; Transon et al, 1996;Von Moltke et al, 1996b;Maenpaa et al, 1998;Wandel et al, 1998;Wang et al, 1999;Martinez et al, 2000;Warrington et al, 2000;Yin et al, 2000;Hamaoka et al, 2001;Andrews et al, 2002;Li et al, 2003) (Fig. 4), 1.0 to 8.9 M for rCYP3A4 (Ghosal et al, 1996;Gibbs et al, 1999;Eiselt et al, 2001;Khan et al, 2002;Obach and Reed-Hagen, 2002;Williams et al, 2002;Yamaori et al, 2003), and 4.1 to 14 M for rCYP3A5 (Gibbs et al, 1999;Williams et al, 2002;Yamaori et al, 2003).…”

Section: Validated Assays For Human Cytochrome P450 Enzymessupporting

confidence: 81%

Validated Assays for Human Cytochrome P450 Activities

Walsky

Obach²

2004

Drug Metab Dispos

465

380

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ABSTRACT:The measurement of the effect of new chemical entities on human cytochrome P450 marker activities using in vitro experimentation represents an important experimental approach in drug development. In vitro drug interaction data can be used in guiding the design of clinical drug interaction studies, or, when no effect is observed in vitro, the data can be used in place of an in vivo study to claim that no interaction will occur in vivo. To make such a claim, it must be assured that the in vitro experiments are performed with absolute confidence in the methods used and data obtained. To meet this need, 12 semiautomated assays for human P450 marker substrate activities have been developed and validated using approaches described in the GLP (good laboratory practices) as per the code of U.S. Federal Regulations. The assays that were validated are: phenacetin O-deethylase (CYP1A2), coumarin 7-hydroxylase (CYP2A6), bupropion hydroxylase (CYP2B6), amodiaquine N-deethylase (CYP2C8), diclofenac 4-hydroxylase and tolbutamide methylhydroxylase (CYP2C9), (S)-mephenytoin 4-hydroxylase (CYP2C19), dextromethorphan O-demethylase (CYP2D6), chlorzoxazone 6-hydroxylase (CYP2E1), felodipine dehydrogenase, testosterone 6␤-hydroxylase, and midazolam 1-hydroxylase (CYP3A4 and CYP3A5). High-pressure liquid chromatography-tandem mass spectrometry, using stable isotope-labeled internal standards, has been applied as the analytical method. This analytical approach, through its high sensitivity and selectivity, has permitted the use of very low incubation concentrations of microsomal protein (0.01-0.2 mg/ml). Analytical assay accuracy and precision values were excellent. Enzyme kinetic and inhibition parameters obtained using these methods demonstrated high precision and were within the range of values previously reported in the scientific literature. These methods should prove useful in the routine assessments of the potential for new drug candidates to elicit pharmacokinetic drug interactions via inhibition of cytochrome P450 activities.Drug-drug interactions are of great interest to scientists involved in drug research, regulatory authorities who are responsible for public safety, physicians, and their patients. Since "polypharmacy," or the practice of simultaneous prescription of more than one drug to treat one or more conditions in a single patient, has become a more common practice, drug interactions have been cited as one of the major reasons for hospitalization and even death (Lazarou et al., 1998). Thus, a great deal of effort is expended by researchers engaged in new drug research in avoiding the development of compounds that will cause drug-drug interactions.The most common mechanism underlying drug-drug interactions is the inhibition of cytochrome P450 activities. Several drugs in common use cause large increases in exposure to other drugs. Examples include ketoconazole, itraconazole, erythromycin, clarithromycin, diltiazem, and nefazodone (CYP3A); quinidine, paroxetine, and terbinafine (CYP2D6); ticlopidine (CYP2C19); ...

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“…The formation of 1Ј-hydroxymidazolam in HLM displayed Michaelis-Menten kinetics in agreement with previous findings (Kronbach et al, 1989). We also confirmed a decrease in metabolite formation for midazolam concentrations above 10 M, which is likely related to CYP3A4 inactivation by 1Ј-hydroxymidazolam (Martínez et al, 2000;Khan et al, 2002).…”

Section: Effect Of Efavirenz On the Midazolam 1ј-hydroxylation By Hlmsupporting

confidence: 75%

“…Initial kinetic studies were conducted to determine the optimal protein concentration for HLM, rCYP3A4, and rCYP3A5 and the optimal incubation time. Midazolam concentrations above 15 M were previously reported to decrease V max in HLM (Martínez et al, 2000). Therefore, HLM (0, 0.005, 0.01, 0.05, 0.1, and 0.2 mg protein/ml) were incubated with 10 M midazolam for 20 min.…”

Section: Chemicalsmentioning

confidence: 99%

Drug Interaction of Efavirenz and Midazolam: Efavirenz Activates the CYP3A-Mediated Midazolam 1′-Hydroxylation In Vitro

Keubler

Weiß²,

Haefeli³

et al. 2012

Drug Metab Dispos

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Modulation of midazolam 1-hydroxylation activity in vitro by neurotransmitters and precursors

Abstract: Brain CYP3A activity could be modulated by some neurotransmitters and precursors.

Cited by 16 publications

References 29 publications

Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu₅: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions

Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu₅: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions

Validated Assays for Human Cytochrome P450 Activities

Drug Interaction of Efavirenz and Midazolam: Efavirenz Activates the CYP3A-Mediated Midazolam 1′-Hydroxylation In Vitro

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Modulation of midazolam 1-hydroxylation activity in vitro by neurotransmitters and precursors

Abstract: Brain CYP3A activity could be modulated by some neurotransmitters and precursors.

Cited by 16 publications

References 29 publications

Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu5: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions

Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu5: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions

Validated Assays for Human Cytochrome P450 Activities

Drug Interaction of Efavirenz and Midazolam: Efavirenz Activates the CYP3A-Mediated Midazolam 1′-Hydroxylation In Vitro

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Resources

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Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu₅: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions

Heterotropic Activation of the Midazolam Hydroxylase Activity of CYP3A by a Positive Allosteric Modulator of mGlu₅: In Vitro to In Vivo Translation and Potential Impact on Clinically Relevant Drug-Drug Interactions