Skip to Main Navigation
Skip to Page Content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Testing Status of C.I. Pigment Red 23 10210-D


CASRN: 6471-49-4

Formula: C24-H17-N5-O7

Synonyms/Common Names

  • 3-Hydroxy-4-((2-methoxy-5-nitrophenyl)azo)-N-(3-nitrophenyl)naphthalene-2-carboxamide
  • Red 23, C.I. Pigment

Short-Term Toxicity

  • 14-Day (Dosed-Feed)  (C60377)  Completed 
    • Rats: F344/N; Mice: B6C3F1
  • 13-Week (Dosed-Feed)  (C60377)  Completed 
    • Rats: F344/N; Mice: B6C3F1
    • Dose: R&M: 0, 3000, 6000, 12500, 25000, 50000 PPM (10 PER GROUP).

Long-Term Carcinogenicity

  • 2 years (Dosed-Feed)  (C60377)  Completed 
    • TR-411 (NIH Number: 93-3142)  (Peer Review Approval 03/11/1991A )
      Toxicology and Carcinogenesis Studies of C.I. Pigment Red 23 (CASRN 6471-49-4) in F344 Rats and B6C3F1 Mice (Feed Studies)
    • Rats: F344/N; Mice: B6C3F1
    • Carcinogenesis Results
      • Male Rats Equivocal Evidence 
      • Female Rats No Evidence 
      • Male Mice No Evidence 
      • Female Mice No Evidence 
    • Dose: R&M: 0, 10000, 25000, 50000 PPM (60 PER GROUP).

Special Studies

  • Absorption Distribution Metabolism Excretion (Gavage)  (S0031)  Completed 
    • Citation: El Dareer SM, Tillery KF, Hill DL. Investigations on the disposition of oral doses of some water-insoluble pigments. Bull Environ Contam Toxicol. 1984 Feb;32(2):171-4.Pubmed Abstract
    • Rats
    • Dose: 5.2 mg/kg.

Genetic Toxicology

  • In Vitro Cytogenetics (CA/SCE)  (115073)  Completed 
    • Sister Chromatid Exchange Positive 
    • Chromosome Aberrations Negative 
  • Salmonella  (721735)  Completed 
    • Citation: Mortelmans, K., Haworth, S., Lawlor, T., Speck, W., Tainer, B., and Zeiger, E. Salmonella mutagenicity tests. II. Results from the testing of 270 chemicals Environ. Mutagen. Vol. 8 (Suppl 7) (1986) 1-119
    •  Positive