PREDICTION OF ABSOLUTE BIOAVAILABILITY FOR DRUGS USING ORAL AND RENALCLEARANCE FOLLOWING A SINGLE ORAL DOSE - A CRITICAL-VIEW

In order to determine the absolute bioavailability, both oral and intr avenous administrations of a drug are often used. Recently a new metho d has been proposed to determine absolute bioavailability in the absen ce of intravenous dose. Following a single oral dose, this method requ ires oral and renal clearance data from normal subjects and renal fail ure patients. The bioavailability is calculated from a plot of oral ag ainst renal clearance following an oral dose, where the inverse of the slope is equal to absolute bioavailability. This study examines the p rediction of absolute bioavailability from the proposed method for eig ht drugs which have a wide range of oral and renal clearance. From thi s study, it appears that the proposed method may not be reliable for t he prediction of absolute bioavailability and further investigation is needed to test the validity of this method. (C) 1997 by John Wiley & Sons, Ltd.