University of Florida Builds First PBPK Model to Predict How Kratom's Mitragynine Behaves in the Human Body

Why it matters

This computational model allows researchers to predict safe human doses of mitragynine and anticipate dangerous drug interactions before clinical trials begin — a critical regulatory milestone toward developing kratom's primary alkaloid as a potential opioid use disorder therapy.

The big picture

Mitragynine has shown promise as a treatment for opioid use disorder, but clinical development has been hampered by the lack of reliable data on how the compound behaves in the human body. Physiologically based pharmacokinetic (PBPK) modeling is a standard FDA-accepted tool used to guide first-in-human dose selection, and its application to mitragynine marks a major step toward legitimate clinical study.

Key findings

• Researchers at University of Florida built and validated a PBPK model for mitragynine using data from rats, dogs, and existing human pharmacokinetic studies
• The model predicts plasma concentration-time profiles of both mitragynine and its active metabolite 7-hydroxymitragynine for single and multiple doses
• Sex-related pharmacokinetic differences were identified; the model was validated separately in male and female animals
• CYP3A4 and CYP2D6 inhibitors had minimal impact on overall mitragynine exposure, but CYP3A4 inhibitors reduced formation of 7-hydroxymitragynine
• Mitragynine increased exposure to midazolam (a CYP3A4 substrate drug) by 2.2–2.7-fold, confirming clinically significant drug interaction potential

What they say

"A physiologically based pharmacokinetic model has been established to support first-in-human dose selection and assess potential drug-drug interactions." — Chiang et al., ACS Pharmacology & Translational Science, 2026

Bottom line

University of Florida scientists have built the first validated computational model for how mitragynine moves through the human body, enabling safer dose predictions and flagging key drug interactions before kratom's primary alkaloid enters clinical trials.