Abstract: Systems and methods for deriving standardized formulations and extracts of herbal remedies, plant extracts, and the like, based upon the rate of absorption and plasma concentration levels attained thereby, when such compositions are administered orally. According to a preferred embodiment, the system comprises a harvested section of small intestine from a mammal and interposed between a first solution having a known quantity of the pharmaceutical composition suspended or dissolved therewithin and a second solution comprising liquid plasma or a buffer solution. The section of intestinal tissue is oriented such that the mucosal layer is oriented toward the first solution whereas the muscularis is oriented toward the second solution. The second solution is periodically analyzed, both qualitatively and quantitatively, to determine the presence and concentration of one or more markers, and in particular any sub-component or metabolites thereof, that has diffused across the intestinal tissue.