Title: phase 0 clinical studies
Long Title: IUPAC Gold Book - phase 0 clinical studies
DOI: 10.1351/goldbook.12707
Status: current

Definition
Exploratory first-in-human trials that involve microdosing of drug to allow the assessment of pharmacokinetic parameters with limited drug exposure.

Note
These trials have no therapeutic or diagnostic intent but are designed to assist decision making by providing bioavailability, metabolism, and other limited data from a small number of patients.

Related Terms
- phase I: https://goldbook.iupac.org//terms/view/12708
- phase II: https://goldbook.iupac.org//terms/view/12709
- phase III: https://goldbook.iupac.org//terms/view/12710
- phase IV: https://goldbook.iupac.org//terms/view/12711

Source
- PAC, 2013, 85, 1725. 'Glossary of terms used in medicinal chemistry. Part II (IUPAC Recommendations 2013)' on page 1746 (https://doi.org/10.1351/PAC-REC-12-11-23)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/12707/html
- json: https://goldbook.iupac.org/terms/view/12707/json
- xml: https://goldbook.iupac.org/terms/view/12707/xml

Citation: Citation: 'phase 0 clinical studies' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.12707
License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.
Collection: If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .
Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.
Accessed: 2026-07-13T14:16:48+00:00