title: Evaluation of aromatic amines with different purities and different solvent vehicles in the Ames test.
abstract: Of all the in vitro mutagenicity assays, the Ames test displays the best correlation with rodent carcinogenicity and therefore carries significant weight with the food and drug regulatory bodies. Aromatic amines (AA) are ubiquitous structural groups in food and drug molecules despite the well-documented mutagenic and carcinogenic propensity for many representatives. Furthermore, recent regulatory guidelines (that is ICH M7) requires the hazard assessment of actual and potential impurities by two complementary (Q)SAR prediction methodologies if no carcinogenicity or bacterial mutagenicity data is available. One methodology should be expert-rule-based and the second should be statistics-based. Having encountered numerous reports of contradictory Ames results for members of this chemotype, we undertook systematic Ames tests on a diverse set of 14 AAs of differing purities in different solvents, and as free bases and their salts. The aim of this work was to investigate the reliability of the Ames test for this chemotype leading to the creation of a reference set of AAs for use by medicinal chemists and in silico modelling. Contrary to previous experience, which led to the investigations reported in this publication, the anticipated transformation from an Ames-positive to an Ames-negative after purification only occurred for one compound. Furthermore, this result proved inconclusive after testing as the HCl salt in DMSO and in water. The anticipated change in class from mutagen to non-mutagen, did not occur and this can be read as evidence for the reliability of the Ames test for AAs.
authors.affiliation: Manchester Institute of Biotechnology (MIB), 131 Princess Street, Manchester M1 7DN, UK; School of Chemistry, Univ. of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Harding
authors.affiliation: Manchester Institute of Biotechnology (MIB), 131 Princess Street, Manchester M1 7DN, UK; School of Chemistry, Univ. of Manchester, Oxford Road, Manchester M13 9PL, UK. Electronic address: pla@manchester.ac.uk.
authors.forename: Paul L A
authors.initials: PL
authors.lastname: Popelier
authors.affiliation: Safety Assessment, GlaxoSmithKline, Park Road, Ware SG12 0DP, UK.
authors.forename: James
authors.initials: J
authors.lastname: Harvey
authors.affiliation: Safety Assessment, GlaxoSmithKline, Park Road, Ware SG12 0DP, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Giddings
authors.affiliation: Molecular Discovery Research, GlaxoSmithKline, Gunnelswood Road, Stevenage SG1 2NY, UK.
authors.forename: Graham
authors.initials: G
authors.lastname: Foster
authors.affiliation: Molecular Discovery Research, GlaxoSmithKline, Gunnelswood Road, Stevenage SG1 2NY, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Kranz
mesh_terms: D000588:Amines / Q000302:isolation & purification* / Q000633:toxicity*; D000818:Animals; D004353:Drug Evaluation, Preclinical / Q000379:methods / Q000592:standards; D009152:Mutagenicity Tests / Q000379:methods* / Q000592:standards; D051381:Rats; D012997:Solvents / Q000302:isolation & purification* / Q000633:toxicity*
chemical_list: D000588:Amines; D012997:Solvents
keywords: Ames test; Aromatic amines; DMSO solvent; Effect purification; Genotoxicity; Mutagenicity