Open AccessSensitivity of dissolution rate to location in the paddle dissolution apparatus
Author(s) -
Healy A. M.,
McCarthy L. G.,
Gallagher K. M.,
Corrigan O. I.
Publication year - 2002
Publication title -
journal of pharmacy and pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 118
eISSN - 2042-7158
pISSN - 0022-3573
DOI - 10.1211/0022357021778529
Subject(s) - dissolution , paddle , diffusion layer , diffusion , mass transfer , dissolution testing , boundary layer , materials science , chemistry , reaction rate constant , chromatography , layer (electronics) , mechanics , thermodynamics , kinetics , composite material , physics , organic chemistry , biopharmaceutics classification system , quantum mechanics
Abstract The aim of the present study was to determine the apparent diffusion boundary layer and dissolution rate constant for various surfaces of compacts and at various locations in the USP paddle dissolution apparatus. Benzoic acid compacts were coated with paraffin wax leaving only the surface under investigation free for dissolution. The dissolution rates for various surfaces at varying locations in the paddle dissolution vessel were determined from the slope of the dissolution profile (amount dissolved (mg) versus time (min)). The apparent diffusion boundary layer and dissolution rate constant were calculated and were found to vary depending on the surface of the compact from which dissolution took place and also on the location and size of the compact. It may be concluded that, in developing models to describe the dissolution from solid dosage forms, it is not accurate to assume constant hydrodynamics and mass transfer rates at all surfaces of the system, or in different locations within the test device. A more exact description of the hydrodyn amics would be necessary in order to precisely model drug dissolution in the paddle dissolution apparatus.