Comparative Assessment of Different Dissolution Apparatus for Floating Drug Delivery Systems

INTRODUCTION Dissolution testing is an in vitro technique of great importance in formulation and development of pharmaceutical dosage forms,as it can be used as a substitute for in vivo studies under strictly defined and specified conditions (1). For the comparison of in vitro dissolution data and for use of such data for in vivo bioequivalence testing and in vitro-in vivo correlations (IVIVC) (1),dissolution testing should be carried out under physicochemically and hydrodynamically defined conditions so that results obtained are accurate and reproducible. New modified release formulation technologies and diversity in dosage form design necessitate the development of new procedures or appropriate modification of the existing apparatus to test alternative dosage forms such as a swellable, floatable drug delivery system (2,8). Traditionally, floating dosage forms were evaluated with the aid of USP type 2 (paddle) apparatus (3),which is associated with a number of shortcomings and drawbacks such as adherence of dosage form to the paddle shaft or sample withdrawal aids (pipette), incomplete exposure to the dissolution medium,and failure to mimic in vivo conditions. Literature study has revealed that in order to overcome these drawbacks and shortcomings,researchers have modified the conventional dissolution method and proposed different modified dissolution apparatus (3–6). This study aims to evaluate positioning of the drug delivery system within the dissolution apparatus over the drug release,which was studied with the aid of four different dissolution apparatus: