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# Guide on Pharmaceutical Co-Crystals
- URL: https://www.fdaweb.com/guide-on-pharmaceutical-co-crystals/
- Published: 2018-02-15T12:00:00.000Z
- Updated: 2026-09-14T23:23:03.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5140769

*Federal Register* notice: FDA has made available a guidance entitled “Regulatory Classification of Pharmaceutical Co-Crystals.” The document provides NDA/ANDA applicants information on the appropriate regulatory classification of pharmaceutical co-crystal solid-state forms. It also provides information about the data that they should submit to support the appropriate classification of a co-crystal as well as the regulatory implications of the classification. To view the notice, click [here](https://www.gpo.gov/fdsys/pkg/FR-2018-02-15/pdf/2018-03133.pdf?ref=fdaweb.com).