The 4-1-2023 edition of 21 CFR Part 73 lists color additives exempt from certification for foods, drugs, cosmetics, and medical devices. Many sections contain direct impurity specifications for arsenic, lead, mercury, cadmium, chromium, nickel, antimony, tin, or aluminum. HMI loads direct not-more-than specifications and gap-logs cross-referenced sections whose inherited specifications are not restated in the local PDF.
Titanium dioxide (§73.575, §73.1575 and §73.2575), 4-1-25 edition
The 2025 edition of the titanium dioxide sections was checked against government section PDFs from govinfo. These are colour-additive specifications. They govern titanium dioxide used to colour a product, not its use as a sunscreen active ingredient, which falls under the over-the-counter sunscreen monograph.
- §73.575 Titanium dioxide (printed pp. 496-497): synthetically prepared TiO2; lead not more than 10 ppm, arsenic 1 ppm, antimony 2 ppm and mercury 1 ppm; loss on ignition at 800 °C not more than 0.5 %; water-soluble substances 0.3 %; acid-soluble substances 0.5 %; TiO2 not less than 99.0 % after drying. Lead, arsenic and antimony are determined in the solution obtained by boiling 10 g in 50 mL of 0.5 N hydrochloric acid for 15 minutes, so those three limits are on an acid-extractable basis.
- §73.1575 (drugs, printed pp. 509-510) and §73.2575 (cosmetics including the eye area, printed p. 518) adopt the identity and specifications of §73.575(a)(1) and (b). §73.1575 allows silicon dioxide and/or aluminium oxide as dispersing aids up to 2 % total.
Zinc oxide (§73.1991 and §73.2991), 4-1-25 edition
The 4-1-25 edition of §73.1991 defines the color additive zinc oxide as a white or yellow-white amorphous powder made by the French (indirect) process, in which zinc metal isolated from the ore is vaporised and then oxidised. It must contain not less than 99 percent zinc oxide, with loss on ignition at 800 °C of not more than 1 percent. Impurity limits are cadmium (as Cd) not more than 15 ppm, mercury (as Hg) not more than 1 ppm, arsenic (as As) not more than 3 ppm and lead (as Pb) not more than 20 ppm. It may be used to colour externally applied drugs, including those used around the eye, in amounts consistent with good manufacturing practice. The section’s source note is 42 FR 37537, July 22, 1977 (printed p.512). The note 42 FR 33723 printed just above §73.1991 belongs to the preceding §73.1647 (copper powder).
Section 73.2991 applies the same identity and specifications (§73.1991(a)(1) and (b)) to zinc oxide used in cosmetics, including around the eye. Its source note is 42 FR 37538, July 22, 1977 (printed p.520).
These specifications govern zinc oxide used as a colour. They do not govern zinc oxide used as the active ingredient of a skin-protectant drug, which is controlled by the OTC monograph and pharmacopoeial grade. At 40 percent zinc oxide, 20 ppm lead in the ingredient would contribute at most 8 ppm (8,000 ppb) lead to a finished product. At 13 percent it would contribute at most 2.6 ppm. This is an arithmetic bound on the colour-additive specification, not a measured value. The 2025 section prints (govinfo CFR-2025-title21-vol1-sec73-1991 and sec73-2991) were received on 2026-09-26 (SHA-256 b0001b75cfa6a3c18cf3f1de11d31e9fd1159a44bf63725c1e3272ec2ab8902d for §73.1991 and 408dd8ad2d83e6f356be072df39cd011e1b82fc26aecbdc97472ff748b60e5d4 for §73.2991).
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