Modular microfluidic system for emulation of human phase I/phase II metabolism

We present a microfluidic device for coupled phase I/phase II metabolic reactions in vitro. The chip consists of microchannels, which are used as packed bed reactor compartments, filled with superparamagnetic microparticles bearing recombinant microsomal phase I cytochrome P450 or phase II conjugating enzymes (UDP-glucuronosyltransferase). Online coupling of the microfluidic device with LC/MS enabled the quantitative assessment of coupled phase I/phase II transformations, as demonstrated for two different substrates, 7-benzyloxy-4-trifluoromethylcoumarin (BFC) and dextromethorphan (DEX). In contrast, conventional sequential one-pot incubations did not generate measurable amounts of phase II metabolites. Because the microfluidic device is readily assembled from standard parts and can be equipped with a variety of recombinant enzymes, it provides a modular platform to emulate and investigate hepatic metabolism processes, with particular potential for targeted small-scale synthesis and identification of metabolites formed by sequential action of specific enzymes.