Mycophenolic acid glucuronidation and its inhibition by non-steroidal anti-inflammatory drugs in human liver and kidney

M. Vietri, A. Pietrabissa, F. Mosca, G. M. Pacifici

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Objective: The aims of this investigation were to study the glucuronidation of mycophenolic acid (MPA) in human liver and kidney and to search for a compound that inhibits MPA glucuronidation among the non-steroidal anti-inflammatory drugs (NSAIDs). Methods: A sensitive and reproducible radiometric assay was developed to measure the rate of MPA glucuronidation in human liver and kidney microsomes. The assay employed uridine 5′-diphosphate-[U-14C]-glucuronic acid (UDPGA) and MPA-glucuronide was isolated by TLC. The final concentrations of UDPGA and MPA necessary were 1 mM (liver), and MPA concentration was 0.5 mM (kidney). The inhibition of MPA glucuronidation was studied with 18 NSAIDs and tacrolimus. Results: Glucuronosyl transferase activity followed Michaelis-Menten kinetics and the Km (mean ± SD; mM) was 0.31 ± 0.06 (liver; n = 5) and 0.28 ± 0.07 (kidney; n = 5; P = 0.555); the Vmax (mean ± SD; nmol/mg per minute) was 5.2 ± 1.4 (liver; n = 5) and 10.5 ± 1.2 (kidney; n = 5; P = 0.0005). The MPA glucuronidation rates (mean ± SD; nmol/min/mg) were 3.3 ± 0.9 (liver; n = 10) and 7.8 ± 1.5 (kidney; n = 10; P = 0.0002). The rate of MPA glucuronidation ranged between 2.0 and 5.1 nmol/mg per minute with a 2.5-fold variation (liver) and between 5.7 and 9.8 nmol/mg per minute with a 1.7-fold variation (kidney). The inhibition study was performed in liver and revealed that the percentage of control ranged from 8% ± 3% (niflumic acid) to 119% ± 16% (Ketoralac). The inhibition curves for MPA glucuronidation rate were determined with the four most effective inhibitors: niflumic acid, flufenamic acid, mefenamic acid and diflunisal. Their IC50 estimates (μM) were 8 ± 1, 19 ± 9, 63 ± 8 and 109 ± 15, respectively (liver), and 8 ± 2, 13 ± 2, 49 ± 4 and 122 ± 18, respectively (kidney). The IC50 estimate for niflumic acid was eightfold lower than the peak plasma levels after a single oral dose of 250 mg of this drug. Conclusion: The human liver and kidney are important sites of MPA glucuronidation. MPA glucuronidation was inhibited to various extents by different NSAIDs and the four most effective inhibitors were niflumic acid, flufenamic acid, mefenamic acid and diflunisal. These drugs have similar molecular structures consisting of two aromatic rings bearing a carboxylic group.

Original languageEnglish
Pages (from-to)659-664
Number of pages6
JournalEuropean Journal of Clinical Pharmacology
Volume56
Issue number9-10
DOIs
Publication statusPublished - 2000

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Mycophenolic Acid
Anti-Inflammatory Agents
Kidney
Liver
Niflumic Acid
Pharmaceutical Preparations
Diflunisal
Flufenamic Acid
Uridine Diphosphate Glucuronic Acid
Mefenamic Acid
Inhibitory Concentration 50
Glucuronic Acid
Uridine Diphosphate
Liver Microsomes
Tacrolimus
Transferases
Molecular Structure

Keywords

  • Glucuronosyl transferase
  • Kidney
  • Liver
  • Mycophenolate mofetil
  • Mycophenolic acid

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Cite this

Mycophenolic acid glucuronidation and its inhibition by non-steroidal anti-inflammatory drugs in human liver and kidney. / Vietri, M.; Pietrabissa, A.; Mosca, F.; Pacifici, G. M.

In: European Journal of Clinical Pharmacology, Vol. 56, No. 9-10, 2000, p. 659-664.

Research output: Contribution to journalArticle

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title = "Mycophenolic acid glucuronidation and its inhibition by non-steroidal anti-inflammatory drugs in human liver and kidney",
abstract = "Objective: The aims of this investigation were to study the glucuronidation of mycophenolic acid (MPA) in human liver and kidney and to search for a compound that inhibits MPA glucuronidation among the non-steroidal anti-inflammatory drugs (NSAIDs). Methods: A sensitive and reproducible radiometric assay was developed to measure the rate of MPA glucuronidation in human liver and kidney microsomes. The assay employed uridine 5′-diphosphate-[U-14C]-glucuronic acid (UDPGA) and MPA-glucuronide was isolated by TLC. The final concentrations of UDPGA and MPA necessary were 1 mM (liver), and MPA concentration was 0.5 mM (kidney). The inhibition of MPA glucuronidation was studied with 18 NSAIDs and tacrolimus. Results: Glucuronosyl transferase activity followed Michaelis-Menten kinetics and the Km (mean ± SD; mM) was 0.31 ± 0.06 (liver; n = 5) and 0.28 ± 0.07 (kidney; n = 5; P = 0.555); the Vmax (mean ± SD; nmol/mg per minute) was 5.2 ± 1.4 (liver; n = 5) and 10.5 ± 1.2 (kidney; n = 5; P = 0.0005). The MPA glucuronidation rates (mean ± SD; nmol/min/mg) were 3.3 ± 0.9 (liver; n = 10) and 7.8 ± 1.5 (kidney; n = 10; P = 0.0002). The rate of MPA glucuronidation ranged between 2.0 and 5.1 nmol/mg per minute with a 2.5-fold variation (liver) and between 5.7 and 9.8 nmol/mg per minute with a 1.7-fold variation (kidney). The inhibition study was performed in liver and revealed that the percentage of control ranged from 8{\%} ± 3{\%} (niflumic acid) to 119{\%} ± 16{\%} (Ketoralac). The inhibition curves for MPA glucuronidation rate were determined with the four most effective inhibitors: niflumic acid, flufenamic acid, mefenamic acid and diflunisal. Their IC50 estimates (μM) were 8 ± 1, 19 ± 9, 63 ± 8 and 109 ± 15, respectively (liver), and 8 ± 2, 13 ± 2, 49 ± 4 and 122 ± 18, respectively (kidney). The IC50 estimate for niflumic acid was eightfold lower than the peak plasma levels after a single oral dose of 250 mg of this drug. Conclusion: The human liver and kidney are important sites of MPA glucuronidation. MPA glucuronidation was inhibited to various extents by different NSAIDs and the four most effective inhibitors were niflumic acid, flufenamic acid, mefenamic acid and diflunisal. These drugs have similar molecular structures consisting of two aromatic rings bearing a carboxylic group.",
keywords = "Glucuronosyl transferase, Kidney, Liver, Mycophenolate mofetil, Mycophenolic acid",
author = "M. Vietri and A. Pietrabissa and F. Mosca and Pacifici, {G. M.}",
year = "2000",
doi = "10.1007/s002280000227",
language = "English",
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pages = "659--664",
journal = "European Journal of Clinical Pharmacology",
issn = "0031-6970",
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TY - JOUR

T1 - Mycophenolic acid glucuronidation and its inhibition by non-steroidal anti-inflammatory drugs in human liver and kidney

AU - Vietri, M.

AU - Pietrabissa, A.

AU - Mosca, F.

AU - Pacifici, G. M.

PY - 2000

Y1 - 2000

N2 - Objective: The aims of this investigation were to study the glucuronidation of mycophenolic acid (MPA) in human liver and kidney and to search for a compound that inhibits MPA glucuronidation among the non-steroidal anti-inflammatory drugs (NSAIDs). Methods: A sensitive and reproducible radiometric assay was developed to measure the rate of MPA glucuronidation in human liver and kidney microsomes. The assay employed uridine 5′-diphosphate-[U-14C]-glucuronic acid (UDPGA) and MPA-glucuronide was isolated by TLC. The final concentrations of UDPGA and MPA necessary were 1 mM (liver), and MPA concentration was 0.5 mM (kidney). The inhibition of MPA glucuronidation was studied with 18 NSAIDs and tacrolimus. Results: Glucuronosyl transferase activity followed Michaelis-Menten kinetics and the Km (mean ± SD; mM) was 0.31 ± 0.06 (liver; n = 5) and 0.28 ± 0.07 (kidney; n = 5; P = 0.555); the Vmax (mean ± SD; nmol/mg per minute) was 5.2 ± 1.4 (liver; n = 5) and 10.5 ± 1.2 (kidney; n = 5; P = 0.0005). The MPA glucuronidation rates (mean ± SD; nmol/min/mg) were 3.3 ± 0.9 (liver; n = 10) and 7.8 ± 1.5 (kidney; n = 10; P = 0.0002). The rate of MPA glucuronidation ranged between 2.0 and 5.1 nmol/mg per minute with a 2.5-fold variation (liver) and between 5.7 and 9.8 nmol/mg per minute with a 1.7-fold variation (kidney). The inhibition study was performed in liver and revealed that the percentage of control ranged from 8% ± 3% (niflumic acid) to 119% ± 16% (Ketoralac). The inhibition curves for MPA glucuronidation rate were determined with the four most effective inhibitors: niflumic acid, flufenamic acid, mefenamic acid and diflunisal. Their IC50 estimates (μM) were 8 ± 1, 19 ± 9, 63 ± 8 and 109 ± 15, respectively (liver), and 8 ± 2, 13 ± 2, 49 ± 4 and 122 ± 18, respectively (kidney). The IC50 estimate for niflumic acid was eightfold lower than the peak plasma levels after a single oral dose of 250 mg of this drug. Conclusion: The human liver and kidney are important sites of MPA glucuronidation. MPA glucuronidation was inhibited to various extents by different NSAIDs and the four most effective inhibitors were niflumic acid, flufenamic acid, mefenamic acid and diflunisal. These drugs have similar molecular structures consisting of two aromatic rings bearing a carboxylic group.

AB - Objective: The aims of this investigation were to study the glucuronidation of mycophenolic acid (MPA) in human liver and kidney and to search for a compound that inhibits MPA glucuronidation among the non-steroidal anti-inflammatory drugs (NSAIDs). Methods: A sensitive and reproducible radiometric assay was developed to measure the rate of MPA glucuronidation in human liver and kidney microsomes. The assay employed uridine 5′-diphosphate-[U-14C]-glucuronic acid (UDPGA) and MPA-glucuronide was isolated by TLC. The final concentrations of UDPGA and MPA necessary were 1 mM (liver), and MPA concentration was 0.5 mM (kidney). The inhibition of MPA glucuronidation was studied with 18 NSAIDs and tacrolimus. Results: Glucuronosyl transferase activity followed Michaelis-Menten kinetics and the Km (mean ± SD; mM) was 0.31 ± 0.06 (liver; n = 5) and 0.28 ± 0.07 (kidney; n = 5; P = 0.555); the Vmax (mean ± SD; nmol/mg per minute) was 5.2 ± 1.4 (liver; n = 5) and 10.5 ± 1.2 (kidney; n = 5; P = 0.0005). The MPA glucuronidation rates (mean ± SD; nmol/min/mg) were 3.3 ± 0.9 (liver; n = 10) and 7.8 ± 1.5 (kidney; n = 10; P = 0.0002). The rate of MPA glucuronidation ranged between 2.0 and 5.1 nmol/mg per minute with a 2.5-fold variation (liver) and between 5.7 and 9.8 nmol/mg per minute with a 1.7-fold variation (kidney). The inhibition study was performed in liver and revealed that the percentage of control ranged from 8% ± 3% (niflumic acid) to 119% ± 16% (Ketoralac). The inhibition curves for MPA glucuronidation rate were determined with the four most effective inhibitors: niflumic acid, flufenamic acid, mefenamic acid and diflunisal. Their IC50 estimates (μM) were 8 ± 1, 19 ± 9, 63 ± 8 and 109 ± 15, respectively (liver), and 8 ± 2, 13 ± 2, 49 ± 4 and 122 ± 18, respectively (kidney). The IC50 estimate for niflumic acid was eightfold lower than the peak plasma levels after a single oral dose of 250 mg of this drug. Conclusion: The human liver and kidney are important sites of MPA glucuronidation. MPA glucuronidation was inhibited to various extents by different NSAIDs and the four most effective inhibitors were niflumic acid, flufenamic acid, mefenamic acid and diflunisal. These drugs have similar molecular structures consisting of two aromatic rings bearing a carboxylic group.

KW - Glucuronosyl transferase

KW - Kidney

KW - Liver

KW - Mycophenolate mofetil

KW - Mycophenolic acid

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