21 CFR 355.20 - Packaging conditions.
(3) Exception. Package size limitations do not apply to anticaries drug products marketed for professional office use only and labeled in accord with § 355.60.
(b) Tight container packaging. To minimize moisture contamination, all fluoride powdered dentifrices shall be packaged in a tight container as defined as a container that protects the contents from contamination by extraneous liquids, solids, or vapors, from loss of the article, and from efflorescence, deliquescence, or evaporation under the ordinary or customary conditions of handling, shipment, storage, and distribution, and is capable of tight reclosure.