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# Pharmaceutical Co-Crystal Classification Guidance
- URL: https://www.fdaweb.com/pharmaceutical-co-crystal-classification-guidance/
- Published: 2018-02-14T12:00:00.000Z
- Updated: 2026-09-14T23:22:37.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5140757

FDA has issued a guidance, *Regulatory Classification of Pharmaceutical Co-Crystals*, to give applicants planning to submit NDAs and ANDAs information on the appropriate regulatory classification of pharmaceutical co-crystal forms. The [guidance](https://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM281764.pdf?ref=fdaweb.com) includes information about the data that applicants should submit to support the appropriate classification of a co-crystal, as well as the regulatory implications of the classification.

FDA says the recommendations in the document apply to materials that it has not previously evaluated and determined to be pharmaceutical co-crystals. The recommendations do not apply to materials that the agency has previously designated as salts, complexes, or other non-crystalline forms.