Inhibitory effect of loperamide on cytochrome P450 3A4 in human liver microsomes

Myung Sup Jeong, Tae Ho Lee, Jeong Woong Moon, Soon Ok Byun, Ji-Young Park, Kyoung Ah Kim

Research output: Contribution to journalArticle

Abstract

Background : Loperamide, a peripherally acting opioid receptor agonist with a methadone-like structure and antidiarrheal action, is mainly metabolized to desmethylloperamide through N-demethylation pathway. It has been reported that CYP2C8 and CYP3A4 might play a crucial role in loperamide Ndemethylation in therapeutic concentrations and loperamide might be an inhibitor of CYP3A4. However, there has been no available data to reveal it. The inhibitory effect of loperamide on CYP3A4 using midazolam 1'-hydroxylation was evaluated in vitro by human liver microsomes. Methods : Various concentrations of loperamide or ketoconazole (a selective and potent inhibitor of CYP3A4) were co-incubated with midazolam in human liver microsomes. CYP3A4-catalyzed midazolam metabolite, 1'-hydroxymidazolam was analyzed by high-performance liquid chromatography (HPLC) to determine the inhibitory potency of loperamide on midazolam 1'-hydroxylation using IC50 (the concentration of inhibitor representing 50% inhibitory potency) and Ki (apparent inhibitory constant) values. Results : Loperamide inhibited concentration-dependently CYP3A4-catalyzed midazolam 1'-hydroxylation with apparent IC50 values of 0.78 μM in human liver microsomes. Graphical analysis showed that loperamide had a potent inhibitory effect on midazolam 1'-hydroxylation with a Ki value of 0.54 μM in a competitive manner. Conclusions : Loperamide had a potent inhibitory effect on CYP3A4-catalyzed midazolam 1'-hydroxylation in human liver microsomes. However the predicted inhibition of loperamide within therapeutic ranges on the metabolism 1'-hydroxylation showed the low possibility of in vivo drug interaction of loperamide with the drug metabolized by CYP3A4.

Original languageEnglish
Pages (from-to)84-91
Number of pages8
JournalJournal of Korean Society for Clinical Pharmacology and Therapeutics
Volume13
Issue number1
Publication statusPublished - 2005 Dec 1
Externally publishedYes

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Loperamide
Cytochrome P-450 CYP3A
Liver Microsomes
Midazolam
Hydroxylation
Inhibitory Concentration 50
Antidiarrheals
Ketoconazole
Methadone
Opioid Receptors
Drug Interactions

Keywords

  • Cytochrome P450 3A4 (CYP3A4)
  • Drug interaction
  • In vitro-in vivo prediction
  • Loperamide

ASJC Scopus subject areas

  • Pharmacology (medical)

Cite this

Inhibitory effect of loperamide on cytochrome P450 3A4 in human liver microsomes. / Jeong, Myung Sup; Lee, Tae Ho; Moon, Jeong Woong; Byun, Soon Ok; Park, Ji-Young; Kim, Kyoung Ah.

In: Journal of Korean Society for Clinical Pharmacology and Therapeutics, Vol. 13, No. 1, 01.12.2005, p. 84-91.

Research output: Contribution to journalArticle

Jeong, Myung Sup ; Lee, Tae Ho ; Moon, Jeong Woong ; Byun, Soon Ok ; Park, Ji-Young ; Kim, Kyoung Ah. / Inhibitory effect of loperamide on cytochrome P450 3A4 in human liver microsomes. In: Journal of Korean Society for Clinical Pharmacology and Therapeutics. 2005 ; Vol. 13, No. 1. pp. 84-91.
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abstract = "Background : Loperamide, a peripherally acting opioid receptor agonist with a methadone-like structure and antidiarrheal action, is mainly metabolized to desmethylloperamide through N-demethylation pathway. It has been reported that CYP2C8 and CYP3A4 might play a crucial role in loperamide Ndemethylation in therapeutic concentrations and loperamide might be an inhibitor of CYP3A4. However, there has been no available data to reveal it. The inhibitory effect of loperamide on CYP3A4 using midazolam 1'-hydroxylation was evaluated in vitro by human liver microsomes. Methods : Various concentrations of loperamide or ketoconazole (a selective and potent inhibitor of CYP3A4) were co-incubated with midazolam in human liver microsomes. CYP3A4-catalyzed midazolam metabolite, 1'-hydroxymidazolam was analyzed by high-performance liquid chromatography (HPLC) to determine the inhibitory potency of loperamide on midazolam 1'-hydroxylation using IC50 (the concentration of inhibitor representing 50{\%} inhibitory potency) and Ki (apparent inhibitory constant) values. Results : Loperamide inhibited concentration-dependently CYP3A4-catalyzed midazolam 1'-hydroxylation with apparent IC50 values of 0.78 μM in human liver microsomes. Graphical analysis showed that loperamide had a potent inhibitory effect on midazolam 1'-hydroxylation with a Ki value of 0.54 μM in a competitive manner. Conclusions : Loperamide had a potent inhibitory effect on CYP3A4-catalyzed midazolam 1'-hydroxylation in human liver microsomes. However the predicted inhibition of loperamide within therapeutic ranges on the metabolism 1'-hydroxylation showed the low possibility of in vivo drug interaction of loperamide with the drug metabolized by CYP3A4.",
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T1 - Inhibitory effect of loperamide on cytochrome P450 3A4 in human liver microsomes

AU - Jeong, Myung Sup

AU - Lee, Tae Ho

AU - Moon, Jeong Woong

AU - Byun, Soon Ok

AU - Park, Ji-Young

AU - Kim, Kyoung Ah

PY - 2005/12/1

Y1 - 2005/12/1

N2 - Background : Loperamide, a peripherally acting opioid receptor agonist with a methadone-like structure and antidiarrheal action, is mainly metabolized to desmethylloperamide through N-demethylation pathway. It has been reported that CYP2C8 and CYP3A4 might play a crucial role in loperamide Ndemethylation in therapeutic concentrations and loperamide might be an inhibitor of CYP3A4. However, there has been no available data to reveal it. The inhibitory effect of loperamide on CYP3A4 using midazolam 1'-hydroxylation was evaluated in vitro by human liver microsomes. Methods : Various concentrations of loperamide or ketoconazole (a selective and potent inhibitor of CYP3A4) were co-incubated with midazolam in human liver microsomes. CYP3A4-catalyzed midazolam metabolite, 1'-hydroxymidazolam was analyzed by high-performance liquid chromatography (HPLC) to determine the inhibitory potency of loperamide on midazolam 1'-hydroxylation using IC50 (the concentration of inhibitor representing 50% inhibitory potency) and Ki (apparent inhibitory constant) values. Results : Loperamide inhibited concentration-dependently CYP3A4-catalyzed midazolam 1'-hydroxylation with apparent IC50 values of 0.78 μM in human liver microsomes. Graphical analysis showed that loperamide had a potent inhibitory effect on midazolam 1'-hydroxylation with a Ki value of 0.54 μM in a competitive manner. Conclusions : Loperamide had a potent inhibitory effect on CYP3A4-catalyzed midazolam 1'-hydroxylation in human liver microsomes. However the predicted inhibition of loperamide within therapeutic ranges on the metabolism 1'-hydroxylation showed the low possibility of in vivo drug interaction of loperamide with the drug metabolized by CYP3A4.

AB - Background : Loperamide, a peripherally acting opioid receptor agonist with a methadone-like structure and antidiarrheal action, is mainly metabolized to desmethylloperamide through N-demethylation pathway. It has been reported that CYP2C8 and CYP3A4 might play a crucial role in loperamide Ndemethylation in therapeutic concentrations and loperamide might be an inhibitor of CYP3A4. However, there has been no available data to reveal it. The inhibitory effect of loperamide on CYP3A4 using midazolam 1'-hydroxylation was evaluated in vitro by human liver microsomes. Methods : Various concentrations of loperamide or ketoconazole (a selective and potent inhibitor of CYP3A4) were co-incubated with midazolam in human liver microsomes. CYP3A4-catalyzed midazolam metabolite, 1'-hydroxymidazolam was analyzed by high-performance liquid chromatography (HPLC) to determine the inhibitory potency of loperamide on midazolam 1'-hydroxylation using IC50 (the concentration of inhibitor representing 50% inhibitory potency) and Ki (apparent inhibitory constant) values. Results : Loperamide inhibited concentration-dependently CYP3A4-catalyzed midazolam 1'-hydroxylation with apparent IC50 values of 0.78 μM in human liver microsomes. Graphical analysis showed that loperamide had a potent inhibitory effect on midazolam 1'-hydroxylation with a Ki value of 0.54 μM in a competitive manner. Conclusions : Loperamide had a potent inhibitory effect on CYP3A4-catalyzed midazolam 1'-hydroxylation in human liver microsomes. However the predicted inhibition of loperamide within therapeutic ranges on the metabolism 1'-hydroxylation showed the low possibility of in vivo drug interaction of loperamide with the drug metabolized by CYP3A4.

KW - Cytochrome P450 3A4 (CYP3A4)

KW - Drug interaction

KW - In vitro-in vivo prediction

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