Application of Similarity Factor (f2) and Time Required to Drug Release (t%) Indicators for Dissolution Profiles Comparison of Paracetamol Tablets

Introduction: The comparison of in vitro dissolution profiles is an integral step during the development of any generic product. However, using merely similarity factor (f2) as a dissolution parameter may not be adequate. Objectives: The present study was conducted to explore whether f2 alone suffices to adequately compare the dissolution profiles of tablets or both f2 and time required to percentage drug release (t%) generate closely similar results. Methods: The reference (R) and two generic paracetamol test products (T1 and T2), each containing 500 mg drug were subjected to dissolution studies under different pH conditions namely 1.2, 4.5 and 6.8. The amount of drug released was quantified using validated UV-Visible spectrophotometric method and results were analysed using bootstrap similarity factor approach and the time required to release 25% (t25%), 50% (t50%) and 75% (t75%) of drug. The data were evaluated statistically using one-way multivariate analysis of variance (MANOVA) followed by post hoc Tukey’s test. Results: T1 tablets demonstrated similarity in the drug release with R product at pH 1.2. Although T2 product did not show any similarity with R at all pH values used yet it depicted rapid release profiles pivotal for an immediate-release product. Both f2 and t% exhibited closely similar results for all sets of data. Conclusion: Application of similarity factor alone may provide reliable results for comparison of dissolution profile. Nevertheless, the time required to release t25%, t50% and t75% may be used along with similarity factor for better interpretation of in vitro dissolution results particularly for potent drugs.