National Toxicology Program

National Toxicology Program

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

Known Uses

In paint, ink, plastic, rubber, and textile printing.

Chemical Properties

Toxicity Effects (HSDB)

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

Long-Term Carcinogenicity

  • 2 years (Dosed-Feed)  (C60377)  Report Complete 
    • 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 Disposition Metabolism Elimination (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

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 
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.