21 CFR 74.1109 - D&C Blue No. 9.
(a)Identity. The color additive D&C Blue No. 9 is principally 7,16-dichloro-6,15 - dihydro - 5,9,14,18 - anthrazine-tetrone.
(b)Specifications. D&C Blue No. 9 shall conform to the following specifications and shall be free from impurities other than those named to the extent that such impurities may be avoided by good manufacturing practice:
(c)Uses and restrictions. D&C Blue No. 9 may be safely used for coloring cotton and silk surgical sutures, including sutures for ophthalmic use, subject to the following restrictions:
(1) The dyed suture shall conform in all respects to the requirements of the United States Pharmacopeia XX (1980).
(2) The quantity of the color additive does not exceed 2.5 percent by weight of the suture.
(3) When the sutures are used for the purposes specified in their labeling, the color additive does not migrate to the surrounding tissue.
(4) If the suture is a new drug, a new-drug application approved pursuant to section 505 of the act is in effect for it.