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(a) Identity. (1) The color additive pyrophyllite is a naturally occurring mineral substance consisting predominantly of a hydrous aluminum silicate, Al2O3-4SiO2-H2 O, intimately mixed with lesser amounts of finely divided silica, SiO2. Small amounts, usually less than 3 percent, of other silicates, such as potassium aluminum silicate, may be present. Pyrophyllite may be identified and semiquantitatively determined by its characteristic X-ray powder diffraction pattern and by its optical properties.
(2) Color additive mixtures made with pyrophyllite are limited to those listed in this subpart as safe and suitable in color additive mixtures for coloring externally applied drugs.
(b) Specifications. Pyrophyllite shall conform to the following specifications:
Lead (as Pb), not more than 20 parts per million.
Arsenic (as As), not more than 3 parts per million.
Lead and arsenic shall be determined in the solution obtained by boiling 10 grams of the pyrophyllite for 15 minutes in 50 milliliters of 0.5N hydrochloric acid.
(c) Uses and restrictions. Pyrophyllite may be safely used in amounts consistent with good manufacturing practice to color drugs that are to be externally applied.
(d) Labeling requirements. The labeling of the color additive and any mixtures prepared therefrom intended solely or in part for coloring purposes shall conform to the requirements of § 70.25 of this chapter.
(e) Exemption from certification. Certification of this color additive is not necessary for the protection of the public health, and therefore batches thereof are exempt from the certification requirements of section 721(c) of the act.
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