title: Exposure-based validation list for developmental toxicity screening assays.
abstract: Validation of alternative assays requires comparison of the responses to toxicants in the alternative assay with in vivo responses. Chemicals have been classified as "positive" or "negative" in vivo, despite the fact that developmental toxicity is conditional on magnitude of exposure. We developed a list of positive and negative developmental exposures, with exposure defined by toxicokinetic data, specifically maternal plasma Cmax . We selected a series of 20 chemicals that caused developmental toxicity and for which there were appropriate toxicokinetic data. Where possible, we used the same chemical for both positive and negative exposures, the positive being the Cmax at a dose level that produced significant teratogenicity or embryolethality, the negative being the Cmax at a dose level not causing developmental toxicity. It was not possible to find toxicokinetic data at the no-effect level for all positive compounds, and the negative exposure list contains Cmax values for some compounds that do not have developmental toxicity up to the highest dose level tested. This exposure-based reference list represents a fundamentally different approach to the evaluation of alternative tests and is proposed as a step toward application of alternative tests in quantitative risk assessment.
authors.affiliation: Procter & Gamble, Cincinnati, Ohio.
authors.forename: George P
authors.initials: GP
authors.lastname: Daston
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Beyer
authors.forename: Edward W
authors.initials: EW
authors.lastname: Carney
authors.forename: Robert E
authors.initials: RE
authors.lastname: Chapin
authors.forename: Jan M
authors.initials: JM
authors.lastname: Friedman
authors.forename: Aldert H
authors.initials: AH
authors.lastname: Piersma
authors.forename: John M
authors.initials: JM
authors.lastname: Rogers
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Scialli
mesh_terms: D001681:Biological Assay; D047109:Fetal Development / Q000187:drug effects*; D057166:High-Throughput Screening Assays; D066298:In Vitro Techniques; D018570:Risk Assessment; D064793:Teratogenesis / Q000187:drug effects*; D013723:Teratogens / Q000633:toxicity*; D018675:Toxicity Tests
chemical_list: D013723:Teratogens
keywords: developmental toxicity; in vitro methods; validation