Vol. 7, Issue 7 (2018)

Author(s):
Tangirala Aruna, Chavali Vindu Bhargavi Yadav, MV Nagabhushanam, Brahmaiah Bonthagarala, D Nagarjuna Reddy and G Ramakrishna

Abstract:
Bioequivalence is a term in pharmacokinetics used to assess the expected in vivo biological equivalence of two proprietary preparations of a drug. If two drugs are bioequivalent it means that they would be expected to be, for all intents and purposes, the same. In determining bioequivalence between two drugs such as a reference drug (Brand) and potential to be test drug (marketed generic drug), pharmacokinetic studies are conducted whereby, each of the drugs are administered in a cross over study to volunteers subjects (healthy individuals). Serum/plasma are obtained at regular intervals and assayed for parent drug (metabolites) concentration. Blood concentration levels are neither feasible nor possible to compare the two drugs, then pharmacodynamic endpoints rather than pharmacokinetic end points are used for comparison. For a pharmacokinetic comparison, the plasma concentration data are used to assess key pharmacokinetic parameters such as area under the curve (AUC), peak concentration (Cmax), time to peak concentration (Tmax), and absorption lag time (tlag). Testing should be conducted at several different doses, especially when the drug displays non-linear pharmacokinetics. If 90% Confidence interval for the ratio of the geometric least square means of natural log transformed Cmax, AUC0-t and AUC0-inf of Test and Reference drugs are within 80.00% to 125.00%, then bioequivalence will be establish.