Predicting dissolution via hydrodynamics: salicylic acid tablets in flow through cell dissolution

A model was established for the dissolution of non-disintegrating salicylic acid tablets as a function of hydrodynamic conditions in the Flow Through Cell system (USP Apparatus 4). The approach was to model the dissolution rate of the material as a function of the Reynold's number, the dimensionless engineering term that describes the degree of turbulence. The dissolution rate of USP calibrator salicylic acid tablets was measured as a function of tablet size, orientation within the cell, dissolution media flow rate, and cell size. All of these variables were found to have an effect on dissolution rate, consistent with theory. An equation to predict this dissolution was established as: N-SH = -21.1 + 12.6 x N-RE(0.5), R-2 = 0.99; 10 < N-re < 292. (C) 2000 Published by Elsevier Science B.V. All rights reserved.