The present disclosure provides an in vitro reagent for evaluating xenobiotic metabolism in a cell culture based assay. The in vitro reagent is an admixture of a cell culture medium and isolated intestinal mucosa comprising villi wherein the intestinal mucosa was eluted from a lumen of the intestine. The isolated mucosa comprises metabolically competent cells. Addition of a xenobiotic test compound to the in vitro reagent allows metabolism of the test compound by the isolated intestinal mucosa comprising villi.
