Contribution of UGT2B17 to the Pharmacokinetics of Diclofenac

Phase

Condition

N/A

Treatment

Diclofenac

curcumin

Clinical Study ID

NCT06053411

20104

Ages 18-65
All Genders
Accepts Healthy Volunteers

Study Summary

The purpose of this pilot study is to gather preliminary data on the (1) contribution of the understudied drug metabolizing enzyme, UDP-glucuronosyltransferase (UGT) 2B17, to the metabolism of a widely used medication, diclofenac, and (2) impact of the UGT2B17 inhibitor and natural product, curcumin, on diclofenac pharmacokinetics. Results will inform future studies aimed to assess the effects of UGT2B17 genetic polymorphisms and co-consumed xenobiotics on the pharmacokinetics and toxicity risk of diclofenac and other UGT2B17 drug substrates.

Eligibility Criteria

Inclusion

Inclusion Criteria:

Aged from 18-64 years and healthy
Not taking any medications (prescription and non-prescription) or dietary/herbalsupplements known to alter the pharmacokinetics of diclofenac or curcumin
Willing to abstain from consuming caffeinated beverages or other caffeine-containingproducts the evening before and morning of the first day of each study arm
Willing to abstain from consuming any alcoholic beverages for one day prior to anystudy day, during the 14-hour inpatient days, and for the outpatient visit(s)following the 14-hour days
Willing to use a secondary method of birth control that does not include theintroduction or discontinuance of hormonal-based birth control (such as abstinence,copper IUD, or condoms)
Have the time to participate
Written informed consent (and assent when applicable) obtained from subject orsubject's legal representative and ability for the subject to comply with therequirements of the study

Exclusion

Exclusion Criteria:

Under the age of 18 or over the age of 65 years
Smoke/vape/chew tobacco products
Use cannabis products, including marijuana, hemp, and other THC- or CBD-containingproducts
Have any current major illness or chronic illness such as (but not limited to)kidney disease, hepatic disease, diabetes mellitus, hypertension, coronary arterydisease, chronic obstructive pulmonary disease, cancer, or HIV/AIDS
History of anemia or any other significant hematologic disorder
History of drug or alcohol addiction or major psychiatric illness
Pregnant or nursing or plan to become pregnant within 3 weeks after participation
History of allergy intolerance to diclofenac or curcumin
Taking concomitant medications, both prescription and non-prescription (includingdietary supplements/herbal products), known to alter the pharmacokinetics ofdiclofenac or curcumin
Taking any turmeric spice or curcumin supplement
Presence of a condition or abnormality that, in the opinion of the Investigator,would compromise participant safety or quality of the data
Out-of-range clinical laboratory value that the study physician considersparticipation in the study a health risk

Study Design

Diclofenac

March 01, 2024

August 18, 2026

Study Description

Diclofenac, a widely used non-steroidal anti-inflammatory drug, has been linked to severe adverse effects such as gastrointestinal ulcers and bleeding and cardiotoxicity. Based on cardiotoxicity reports, US and European regulatory agencies withdrew over-the-counter (OTC) diclofenac, requiring the drug to be a prescription-only medication. However, diclofenac remains OTC in many countries, including Australia, China, and India, among others. Reported metabolic pathways of diclofenac in the liver are mediated by the prominent drug metabolizing enzyme, cytochrome P450 (CYP) 2C9, and the conjugative enzyme, UDP-glucuronosyltransferase (UGT) 2B7. However, recent in vitro and in silico data indicated that diclofenac is metabolized almost exclusively by a less-studied UGT, UGT2B17, in the intestine.

UGT2B17 is among the most genetically polymorphic enzymes, with highly prevalent copy number variations (CNVs). Individuals homozygous for the null allele, UGT2B172 (CNV=0), are considered poor metabolizers (PMs), whereas those homozygous for the reference allele, UGT2B171/*1 (CNV=2), are considered extensive metabolizers (EMs). Deletion of this gene may lead to large interindividual variability in the pharmacokinetics - and toxicity risk - for patients taking diclofenac and other UGT2B17 substrates, including vorinostat, MK7426, tamoxifen, exemestane, and testosterone. Collectively, considering UGT2B17 CNVs on the metabolism of these drugs is critical to ensure consistent and optimum safety, efficacy, and patient outcomes.

Recent preliminary data showed that curcumin, a principal curcuminoid of the natural product turmeric, is a potent inhibitor of UGT2B17. Turmeric is used worldwide and was the 2nd top-selling herbal supplement in the US in 2021, with nearly $100 million in total sales. Considering both turmeric/curcumin and diclofenac are used for arthritis and other inflammatory conditions, there is a high likelihood of patients co-consuming curcumin and diclofenac, raising concerns for variable diclofenac pharmacokinetics and toxicity risk.

The purpose of this pilot study is to gather preliminary data on the (1) contribution of UGT2B17 to diclofenac metabolism and (2) impact of curcumin co-administration on diclofenac pharmacokinetics. Results will inform future studies aimed to evaluate the effects of UGT2B17 genetic polymorphisms and co-consumed xenobiotics on the pharmacokinetics and toxicity risk of diclofenac and other UGT2B17 drug substrates.

Connect with a study center

Washington State University College of Pharmacy and Pharmaceutical Sciences
Spokane, Washington 99202
United States
Active - Recruiting

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