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Hydrodynamik kompendialer Lösungsgeschwindigkeits-Testapparaturen

Paddle und Basket

Steffen M. Diebold*)und Jennifer B. Dressman

Institut für Pharmazeutische Technologie, Johann Wolfgang Goethe-Universität Frankfurt/Main

Hydrodynamics in Compendial Dissolution Apparatus / Paddle and basket

The objective of the present study was to examine the hydrodynamics of compendial in vitro dissolution testers. Hydrodynamics of two compendial dissolution testers (paddle and basket) were directly characterized by means of an ultrasound pulse echo method. The fluid velocities within the dissolution vessels correlated well and in a linear manner with the rotational speed (rpm) of the paddle and the basket. On the basis of this correlation it is possible to calculate the linear velocity in the dissolution medium at any rotational speed. Fluid velocities using the basket method were determined to range between 0.3 and 5 cm/s (25 to 200 rpm) and for the paddle method to range between 1.8 and 37 cm/s. The empirically determined fluid velocities can be used to predict the in vitro dissolution rates of pure drugs in paddle and basket tests on an a priori basis.