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# Guide on Drug Elemental Impurities
- URL: https://www.fdaweb.com/guide-on-drug-elemental-impurities/
- Published: 2020-03-12T12:00:00.000Z
- Updated: 2026-09-14T16:06:59.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5146309

*Federal Register* notice: FDA has made available a final guidance entitled “Q3D(R1) Elemental Impurities.” The International Council for Harmonization-prepared document revises the existing guidance “Q3D Elemental Impurities” and provides an updated permitted daily exposure for the cadmium inhalation route of exposure. The updated PDE of 3 micrograms/day is based on a modifying factor approach like that used for calculating the PDEs for the cadmium oral and parenteral routes of exposure. To view the notice, click [here](https://www.govinfo.gov/content/pkg/FR-2020-03-11/pdf/2020-04995.pdf?ref=fdaweb.com).