Mechanistic Approach to Understanding the Influence of USP Apparatus I and II on Dissolution Kinetics of Tablets with Different Operating Release Mechanisms.

This article provides an analysis of dissolution kinetics associated with formulations subjected to different dissolution methods with the purpose of revealing credible direction on selection of apparatus type and hydrodynamics on in vitro drug release profiles using three different formulations. The dissolution kinetics of immediate release (IR) and controlled release (CR) ibuprofen tablets under different hydrodynamic conditions were determined, and potential existence of any correlation between USP apparatus I and II were analyzed using adequate kinetic models. Two types of CR tablets based on PEO (polyethylene oxide-N80) and HPMC (hydroxypropyl methylcellulose- K100M) polymers were prepared. Marketed ibuprofen 200-mg IR tablets were also used. Dissolution studies were carried out using USP 34 apparatuses I and II methods at stirring speed of 100 and 50 rpm in 900 mL phosphate buffer, pH 7.2 at 37°C. The drug release profiles for each formulation was determined and statistically analyzed using model-dependent, model-independent (f ), and ANOVA methods. No significant dissolution differences existed between IR tablets, whereas CR tablets were significantly impacted by apparatus types and hydrodynamics. PEO matrices displayed higher sensitivity to hydrodynamics relative to HPMC matrices, and differences in dissolution profiles were confirmed by ANOVA and boxplot analysis. It is concluded that in the case of CR systems, selection of apparatus type and adherence to the monograph specifications and hydrodynamic conditions is critical, while for IR tablets, both apparatus types and agitation rates had no significant impact on drug release rate, suggesting the possibility of apparatus interchangeability if desired.