Makers of generic drugs are required to show that their generic drugs do not differ significantly from the "reference" or brand name drugs that they imitate. one aspect in which the generic drugs might differ is their extent of absorption in the blood. twelve subjects were available for the study. six were randomly selected to receive the generic drug first and then, after a washout period, receive the "reference" drug. the remaining six received the "reference" drug first, followed by the generic drug after the washout period.