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# Guide on OTC Maximal Usage Drug Trials
- URL: https://www.fdaweb.com/guide-on-otc-maximal-usage-drug-trials/
- Published: 2018-05-23T12:00:00.000Z
- Updated: 2026-09-15T00:07:22.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5141518

*Federal Register* notice: FDA has made available a draft guidance for industry entitled “Maximal Usage Trials for Topical Active Ingredients Being Considered for Inclusion in an Over-the-Counter Monograph: Study Elements and Considerations.” The document addresses FDA’s current thinking on the conduct of *in vivo* absorption trials for topical active ingredients that are under consideration for inclusion in an over- the-counter monograph. To view the notice, click [here](https://www.gpo.gov/fdsys/pkg/FR-2018-05-23/pdf/2018-10993.pdf?ref=fdaweb.com).