The present study highlights about assessment of
bioequivalence using urinary excretion data. A rapid method for assessing the
bioavailability of a drug is the use of urinary excretion data. This method is
based on the principle that the urinary excretion rate of an 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 the test (T) and reference (R) formulations. Urine
metabolite excretion data are not used to assess bioavailability since the drug
undergoes metabolism in the body, anatomically and the rate of metabolism may
vary for different reasons. This method applies to drugs that are excreted
unchanged in the urine, e.g., some thiazide diuretics, sulfonamides, biguanides
and drugs that act on the urinary tract, such as urinary antiseptics
(nitrofurantoin and hexamine). It is concluded from this study that the
formulations Glucophage and Metformin (tablets 850 mg) exhibit a similar
elimination rate, which indicates a similarity in their bioavailability and
bioequivalence. Based on this study, some drugs such as metformin can therefore
be evaluated to simulate and predict absorption through urinary excretion data.
Due to the high invasiveness of bioequivalence/bioavailability conventional
studies, the prediction of absorption can be performed using the urinary
excretion method. Furthermore, the urinary excretion methodology represents low
costs, it is a less invasive method, and its throughput is viable when compared
to the conventional method with blood samples.
Author(s)details:-
Eva Troja
Profarma SH.A. Pharmaceutical Industry, Tirana, Albania.
Leonard Deda
Department of Biomedical Sciences, Faculty of Medicine, University of
Medicine, Tirana, Albania.
Please See the book
here :- https://doi.org/10.9734/bpi/prrat/v2/679
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