Statistical methods in bioequivalence studies and an application

Objective: Statistical calculations are the main parts of a study to prove the thesis of the researches in the drug development researches. Statistical analysis is used in each step of the study, from experimental design to decision and conclusion. The aim of this study was to give information on bioequivalence theory, clarify statistical methods for bioequivalence and show the feasibility of these methods by using the original data. Material and Methods: The application of the methods explained in the study was performed using the original data. Twenty-four participants were included in the study. Average, population and individual bioequivalence methods were used for bioequivalence of the test and reference drugs. Results: Pain killer test and reference drugs were given to healty participants for the bioequivalence study. The participants were examined by obtaining blood samples at specific time points during the ten hours following one oral dose of the drug. Blood samples were stored in deep freeze at -70 degrees C after processing. The density values of the elements in the blood were determined by a reliable method. In average bioequivalence method, the 90% lower and upper bound values of Cmax and AUCO-infinity parameters were between 80% and 120%. Besides, power values were close to 1. In population and individual bioequivalence methods, the difference between test and reference drug values were small for Cinax and AUCO-infinity parameters and their proportion values were within the +/- 20% interval. In addition, the variance values were small. The average, population and individual bioequivalence methods proved satisfactory for the bioequivalence for Cmax and AUCO-infinity parameters. Conclusion: Test and reference drugs were bioequivalent for average, population and individual bioequivalence methods.