1. Regulatory classification of pharmaceutical co-crystals Publication: Silver Spring, MD : Center for Drug Evaluation and Research, February 2018 Subject(s): Chemistry, Pharmaceutical -- classificationChemistry, Pharmaceutical -- standardsCrystallization -- classificationInvestigational New Drug ApplicationBiological AvailabilityHumansUnited StatesUnited States. Department of Health and Human Services.United States. Food and Drug Administration.