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GUIDANCE DOCUMENT

Clinical Pharmacology Considerations for Human Radiolabeled Mass Balance Studies May 2022

Download the Draft Guidance Document Read the Federal Register Notice
Draft

Not for implementation. Contains non-binding recommendations.

This guidance is being distributed for comment purposes only.

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Although you can comment on any guidance at any time (see 21 CFR 10.115(g)(5)), to ensure that the FDA considers your comment on a draft guidance before it begins work on the final version of the guidance, submit either online or written comments on the draft guidance before the close date.

If unable to submit comments online, please mail written comments to:

Dockets Management
Food and Drug Administration
5630 Fishers Lane, Rm 1061
Rockville, MD 20852

All written comments should be identified with this document's docket number: FDA-2022-D-0113

Docket Number:
FDA-2022-D-0113
Issued by:
Guidance Issuing Office
Center for Drug Evaluation and Research

This guidance describes the FDA’s recommendations regarding clinical pharmacology considerations for conducting human radiolabeled mass balance studies of investigational drugs, including: (1) deciding whether and when to conduct the study, (2) designing the study, and (3) reporting results. This guidance does not cover animal mass balance studies, safety testing of drug metabolites, or recommendations for selecting the radioactive dose.

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