21 CFR 358.303 - Definitions.
As used in this subpart:
(a) Ingrown toenail relief drug product. A drug product applied to an ingrown toenail that relieves pain or discomfort either by softening the nail or by hardening the nail bed.
(b) Retainer ring. A die cut polyethylene foam pad coated on one side with medical grade acrylic pressure-sensitive adhesive. The retainer ring has slots, center-cut completely through the foam with the cut of sufficient size to allow for localization of an active ingredient in a gel vehicle to a specific target area. The retainer ring is used with adhesive bandage strips to place over the retainer ring to hold it in place.