1. Q4B evaluation and recommendation of pharmacopoeial texts for use in the ICH regions: annex 1(R1) : residue on ignition/sulphated ash general chapter Publication: Silver Spring, MD : Center for Drug Evaluation and Research, September 2017 Subject(s): Chemistry, PharmaceuticalDrug ApprovalPharmacopoeias as Topic -- standardsCongresses as TopicInternational CooperationSulfurHumansEuropeJapanUnited StatesUnited States. Department of Health and Human Services.United States. Food and Drug Administration.