Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 1 de 1
Filtrar
Mais filtros

Bases de dados
Ano de publicação
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Environ Toxicol Chem ; 38(3): 548-560, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30569498

RESUMO

In vitro biotransformation studies were performed to support the bioaccumulation assessment of 3 hydrophobic organic ultraviolet filters (UVFs), 4-methylbenzylidene camphor (4-MBC), 2-ethylhexyl-4-methoxycinnamate (EHMC), and octocrylene. In vitro depletion rate constants (kdep ) were determined for each UVF using rainbow trout liver S9 fractions. Incubations performed with and without added cofactors showed complete (4-MBC) or partial (EHMC and octocrylene) dependence of kdep on addition of the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH), suggesting that hydrolysis of EHMC and octocrylene by NADPH-independent enzymes (e.g., carboxylesterases) is an important metabolic route. The concentration dependence of kdep was then evaluated to estimate Michaelis-Menten parameters (KM and Vmax ) for each UVF. Measured kdep values were then extrapolated to apparent whole-body biotransformation rate constants using an in vitro-in vivo extrapolation (IVIVE) model. Bioconcentration factors (BCFs) calculated from kdep values measured at concentrations well below KM were closer to empirical BCFs than those calculated from kdep measured at higher test concentrations. Modeled BCFs were sensitive to in vitro binding assumptions employed in the IVIVE model, highlighting the need for further characterization of chemical binding effects on hepatic clearance. The results suggest that the tested UVFs are unlikely to accumulate to levels exceeding the European Union Registration, Evaluation, Authorisation, and Restriction regulation criterion for bioaccumulative substances (BCF > 2000 L kg-1 ). However, consideration of appropriate in vitro test concentrations and binding correction factors are important when IVIVE methods are used to refine modeled BCFs. Environ Toxicol Chem 2019;38:548-560. © 2018 SETAC.


Assuntos
Oncorhynchus mykiss/metabolismo , Protetores Solares/metabolismo , Acrilatos/química , Acrilatos/metabolismo , Animais , Biotransformação , Cânfora/análogos & derivados , Cânfora/química , Cânfora/metabolismo , Cinamatos/química , Cinamatos/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Fígado/metabolismo , Protetores Solares/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA