Interpretation of dissolution rates by the reaction fractal dimensions

The dissolution behaviour of particles in the size range similar to 50 nm to similar to 5 mm has been interpreted by the concepts of fractal geometry. Three typical values of the dissolution fractal dimensions D-R may be distinguished. The dissolution behaviour of agglomerated particles (Smoluchowskian particles) has a characteristic value of the dissolution fractal oo dimension between 0.0 less than or equal to D-R less than or equal to 1.0. Compact particles suffering vigorous Brownian motion (Brownian particles) can be characterized by D-R values between 1.0 less than or equal to D-R less than or equal to 2.0. Compact crystals bigger than similar to 10 mu m show a characteristic dissolution fractal dimension between 2.0 less than or equal to D-R less than or equal to 3.0.