Code of Federal Regulations Title 21. Food and Drugs § 21.73.3115 2–[[2,5–Diethoxy–4–[ (4–methylphenyl) thiol]phenyl]azo]–1,3,5–benzenetriol

(a) Identity. The color additive 2–[[2,5–diethoxy–4–[ (4–methylphenyl)thio]phenyl]azo]–1,3,5–benzenetriol is formed in situ in soft (hydrophilic) contact lenses.

(b) Uses and restrictions. The color additive 2–[[2,5–diethoxy–4–[ (4–methylphenyl)thio]phenyl]azo]–1,3,5–benzenetriol may be safely used to mark soft (hydrophilic) contact lenses with the letter R or the letter L for identification purposes subject to the following restrictions:

(c) Labeling. The label of the color additive shall conform to the requirements of § 70.25 of this chapter.

(d) Exemption from certification. Certification of this color additive is not necessary for the protection of the public health, and therefore the color additive is exempt from the certification requirements of section 721(c) of the act.