Comparison of the USP Apparatus 2 and 4 for testing the in vitro release performance of ibuprofen generic suspensions

Abstract

Objective: The aim of this study was the comparison of the in vitro release performance of ibuprofen generic suspensions and reference, based on the hydrodynamic environment generated by the flow-through cell method (USP Apparatus 4). Results were compared with those obtained by the use of the USP Apparatus 2. Methods: The Advil® suspension (2 g/100 ml) and two generic formulations with the same dose were tested. Dissolution studies were carried out using a USP Apparatus 4 Sotax CE6 with 22.6 mm cells, laminar flow at 16 ml/min, and pH 7.2 phosphate buffer at 37.0±0.5 °C as dissolution medium. Ibuprofen was quantified spectrophotometrically at 222 nm. The in vitro release of the three drug products were studied using the USP Apparatus 2. The dissolution profiles of generic products were compared with the reference by model-independent, model-dependent, and analysis of variance (ANOVA)-based comparisons. Results: The dissolution profile of the generic product A was similar to the dissolution profile of reference, only with the use of the USP Apparatus 4. The f2 similarity factor was>50 and no significant differences were found with dissolution efficiency data (*P>0.05). Similar results were found with the comparison of t50% and t63.2% values. Similar dissolution profiles between generic product A and reference were also found with ANOVA-based comparisons. Conclusion: The flow-through cell method was adequate for study the in vitro release of ibuprofen suspensions. It is necessary to evaluate the in vivo performance of the drug products used in order to estimate the predictability of the proposed methodology.