Metabolism is the major elimination pathway of a drug from the body initiated by drug metabolizing enzymes (DMEs). DMEs are present mainly in the liver, intestine, and blood and facilitate the excretion of xenobiotics from the body by converting lipophilic drugs into hydrophilic compounds. Cytochrome P450 enzymes (CYPs) are responsible for the clearance of a majority of drugs on the market, and, accordingly, much emphasis has been placed on understanding the role of CYPs in metabolism, clearance, drug-drug interactions, and oral bioavailability [1].