Biotransformation rates of Ugilec 141® (tetrachlorobenzyltoluenes) in rat and trout microsomes

Abstract In vitro biotransformation rates of tetrachlorobenzyltoluene (TCBT) isomers 3,3′,4,4′-Cl 4 -2-Me (TCBT 87), 3,3′,4,4′-Cl 4 -5-Me (TCBT 88), and 3,3′,4′,5-Cl 4 -4-Me (TCBT 94) were determined using trout and rat hepatic microsomes. The disappearance of the TCBTs from the in vitro system followed first-order kinetics. The estimated biotransformation constants ( k ) for the rat ranged from 0.96 to 4.14 h −1 . Biotransformation rates for trout microsomes were much lower and ranged from 0.009 to 0.017 h −1 .