<i>In vitro</i> metabolism assessment of thiacloprid in rainbow trout and rat by LC-UV and high resolution-mass spectrometry
Creators: name: Serrano, Jose
name: Kolanczyk, Richard C.
name: Blackwell, Brett R.
name: Sheedy, Barbara R.
name: Tapper, Mark A.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Pharmacology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: FOS: Chemical sciences
subject: Ecology
subject: Science Policy
subject: 69999 Biological Sciences not elsewhere classified
subject: Inorganic Chemistry

description: Thiacloprid (THI) is a widely used neonicotinoid insecticide where concerns have been raised regarding low absorption by crops, substantial distribution in surrounding areas, and potential adverse effects to terrestrial and aquatic organisms.Prior to this study, there was very limited information addressing the <i>ex vivo</i> (precision-cut liver slices) metabolism of THI by fish species and the metabolic pathways regulating its potential for adverse effects.The <i>in vitro</i> and <i>ex vivo</i> biotransformation pathway of THI is defined by the formation of three primary metabolites (TM1, TM2 and TM3) via separate paths differentiated by reductive decyanation, reductive dechlorination with hydration and dealkylation processes, respectively.Kinetic rates were calculated for the rat microsomal decyanation of THI into TM1 (<i>K<sub>m</sub></i> = 299.2 µM and <i>V<sub>max</sub></i> = 5.3 pmol/min/mg), and for the dealkylation of THI into TM3 (<i>K<sub>m</sub></i> = 368.9 µM and <i>V<sub>max</sub></i> = 3.95 pmol/min/mg).Formation confirmation and identity inference of THI metabolites in absence of standards were achieved by LC-UV and High Resolution-MS strategies.The <i>in vitro</i> and <i>ex vivo</i> metabolic products of THI are conserved both across species (rat and Rainbow trout) and levels of biological organization (microsomes and liver slices), as previously reported for the neonicotinoid insecticides Imidacloprid and Acetamiprid. Thiacloprid (THI) is a widely used neonicotinoid insecticide where concerns have been raised regarding low absorption by crops, substantial distribution in surrounding areas, and potential adverse effects to terrestrial and aquatic organisms. Prior to this study, there was very limited information addressing the <i>ex vivo</i> (precision-cut liver slices) metabolism of THI by fish species and the metabolic pathways regulating its potential for adverse effects. The <i>in vitro</i> and <i>ex vivo</i> biotransformation pathway of THI is defined by the formation of three primary metabolites (TM1, TM2 and TM3) via separate paths differentiated by reductive decyanation, reductive dechlorination with hydration and dealkylation processes, respectively. Kinetic rates were calculated for the rat microsomal decyanation of THI into TM1 (<i>K<sub>m</sub></i> = 299.2 µM and <i>V<sub>max</sub></i> = 5.3 pmol/min/mg), and for the dealkylation of THI into TM3 (<i>K<sub>m</sub></i> = 368.9 µM and <i>V<sub>max</sub></i> = 3.95 pmol/min/mg). Formation confirmation and identity inference of THI metabolites in absence of standards were achieved by LC-UV and High Resolution-MS strategies. The <i>in vitro</i> and <i>ex vivo</i> metabolic products of THI are conserved both across species (rat and Rainbow trout) and levels of biological organization (microsomes and liver slices), as previously reported for the neonicotinoid insecticides Imidacloprid and Acetamiprid.