Department of Medicine, University of Health and Medical Sciences, Tirana, Albania
Mini Review
Assessment of Bioequivalence Using Urinary Excretion Data
Author(s): Eva Troja* and Leonard Deda
A rapid method for assessing the bioavailability of the drug is the use of urinary excretion data. This method is based
on the principle that the urinary excretion rate of unchanged drug is directly proportional to the plasma
concentration of the drug. So bioavailability can be calculated as the ratio of the total amount of unchanged drug in
urine after administration of test (T) and reference (R) formulations. Urine metabolite excretion data are not used to
assess bioavailability since the drug undergoes metabolism in different locations and the rate of metabolism may vary
for different reasons. This method applies to drugs that are excreted unchanged in the urine, eg, some thiazide
diuretics, sulfonamides, and drugs that act on the urine, such as urinary antiseptics (Nitrofurantoin and Hexamine). .. View more»