Most drugs are non-polar lipid soluble. This is the easiest way for drugs to move through via absorption. Most of these drugs will be excreted through the kidneys, through the urinary system. By doing this, it could actually make the drug active or it couldn't make it inactive or less active. So you may create a drug that isn't active, but then once it gets to the liver or other tissues, it's then changed because it's not just the liver that does the metabolism here.