In the above pair of experiments, Hµrelhuman™ microlivers were exposed to midazolam in the presence of, respectively, CYP 3A4 inducer rifampin and CYP 3A4 potent inhibitor ketoconazole, which were repeat-administered every 24 hours for 72 hours.  As measured by 1-OH midazolam formation, the microlivers demonstrated time- and concentration-dependent induction and inhibition of enzyme activity.   Exposure to midazolam was continued at 24-hour intervals after administration of rifampin and ketoconazole had ceased.  The microlivers demonstrated a return to basal enzyme activity in a time-dependent manner, illustrating the dynamic responsiveness and resilience of Hµrel®’s metabolic competency.