21 CFR 207.37 - What restrictions pertain to the use of the NDC?
(a) A product may be deemed to be misbranded if an NDC is used:
(1) To represent a different drug than the drug for which the NDC has been assigned, as described in § 207.33;
(2) To denote or imply FDA approval of a drug; or
(3) On products that are not subject to parts 207, 607 of this chapter, or 1271 of this chapter, such as dietary supplements and medical devices.
(b) If marketing is resumed for a discontinued drug, and no changes have been made to the drug that would require a new NDC under § 207.35, the drug must have the same NDC that was assigned to it as described in § 207.33, before marketing was discontinued.