National drug code directory
"Drug establishments are required to provide FDA with a current list of all drugs manufactured, prepared, propagated, compounded or processed for sale in the U.S. at their facilities. Drugs are identified and reported using a unique, three-segment number called the National Drug Code (NDC) which serves as the FDA's identifier for drugs. FDA publishes the listed NDC numbers in the NDC Directory which is updated daily"--Background information
Sitio web, English, 2001
U.S. Department of Health and Human Services, Public Health Service, Food and Drug Administration, Center for Drug Evaluation and Research, Division of Data Management and Services, Silver Spring, MD, 2001