Electrochemistry-on-chip for on-line conversions in drug metabolism studies.

We have designed an integrated 3-electrode electrochemical cell on-chip with high analyte conversion rates for use in drug metabolism studies. The electrochemical cell contains platinum working and counter electrodes and an iridium oxide pseudo-reference electrode. The pseudo-reference electrode has a pH sensitivity of -52 mV/s, and thus will provide a constant potential in solutions with known and constant pH. The average drift of the iridium oxide electrode is below 5 mV for a typical 15 min conversion experiment. We have been able to mimic the oxidative drug metabolism reactions catalysed by enzymes of the cytochrome P-450 family, normally occurring in the human body. With the chip, the different reaction products of both rat liver cell microsome and human liver cell microsome incubations have been observed.