[Code of Federal Regulations]
[Title 21, Volume 1]
[Revised as of April 1, 2001]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR73.1298]

[Page 361-362]
 
                        TITLE 21--FOOD AND DRUGS
 
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN 
                                SERVICES
 
PART 73--LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION--Table of Contents
 
                            Subpart B--Drugs
 
Sec. 73.1298  Ferric ammonium ferrocyanide.

    (a) Identity. (1) The color additive ferric ammonium ferrocyanide is 
the blue pigment obtained by oxidizing under acidic conditions with 
sodium dichromate the acid digested precipitate resulting from mixing 
solutions of ferrous sulfate and sodium ferrocyanide in the presence of 
ammonium sulfate. The oxidized product is filtered, washed, and dried. 
The pigment consists principally of ferric ammonium ferrocyanide with 
smaller amounts of ferric ferrocyanide and ferric sodium ferrocyanide.
    (2) Color additive mixtures for drug use made with ferric ammonium 
ferrocyanide may contain only those

[[Page 362]]

diluents listed in this subpart as safe and suitable for use in color 
additive mixtures for coloring drugs.
    (b) Specifications. Ferric ammonium ferrocyanide shall conform to 
the following specifications and shall be free of impurities other than 
those named to the extent that the other impurities may be avoided by 
good manufacturing practice:

Oxalic acid or its salts, not more than 0.1 percent.
Water soluble matter, not more than 3 percent.
Water soluble cyanide, not more than 10 parts per million.
Volatile matter, not more than 4 percent.
Lead (as Pb), not more than 20 parts per million.
Arsenic (as As), not more than 3 parts per million.
Nickel (as Ni), not more than 200 parts per million.
Cobalt (as Co), not more than 200 parts per million.
Mercury (as Hg), not more than 1 part per million.
Total iron (as Fe corrected for volatile matter), not less than 33 
percent and not more than 39 percent.

    (c) Uses and restrictions. Ferric ammonium ferrocyanide may be 
safely used in amounts consistent with good manufacturing practice to 
color externally applied drugs, including those for use in the area of 
the eye.
    (d) Labeling requirements. The label of the color additive and of 
any mixtures prepared therefrom intended solely or in part for coloring 
purposes shall conform to the requirements of Sec. 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 
therfore batches thereof are exempt from the certification requirements 
of section 721(c) of the act.

[42 FR 38562, July 29, 1977, as amended at 44 FR 28322, May 15, 1979]