Determination of in-vitro equivalence of paracetamol tablets

Abstract

Bioequivalence studies are the usually accepted method to determine the therapeutic equivalence of two drug products. Because in-vivo bioequivalence studies are time consuming and expensive to conduct, major regulatory authorities have introduced biowaivers for some selected medicines belonging to BCS class 1 and III drugs. Comparative dissolution tests are used in biowaiver procedure to waiver the bioequivalence requirement. We performed this study to see whether two brands of paracetamol tablets are bioequivalent using the in-vitro methodology. In the first stage of this research study, British Pharmacopeia 2012 quality tests were performed on the two selected paracetamol tablet products to determine whether they are pharmaceutically equivalent. In the second stage in-vitro equivalence of the two products was determined using the biowaiver testing procedure given by the World Health Organization. Dissolution profiles were generated at pH values, 1.2, 4.5 and 6.8. Results were compared through two model independent methods, difference factor (f 1) and similarity factor (f 2). The two paracetamol tablet products tested, complied with all the quality requirements of the British Pharmacopeia 2012. For the two products, the difference factor (f 1) was below the 15 and similarity factor (f 2) was above the 50 in all dissolution test conditions. These results confirm that the two products are pharmaceutically equivalent. The test product is also bioequivalent to the reference product in-vitro, and therefore they can be interchangeable during clinical use. This study shows that in-vivo bioequivalence testing can be waived using the in-vitro method, for some pharmaceutical products such as paracetamol tablets.