The paper examines the use of the fractal dimension for the expression of the shape of random aggregates of primary particles of four powders for pharmaceutical dusting powders. The values within a range from 1.14 to 1.24 are compared with the results of the equilibrium gravitational classification within a range from 15 to 45 mm. Vacillation of the fractal dimension is influenced by the values of the specific surface determined from the parameters of the RRS-distribution of elutriation. The fractal dimension extends the morphological characteristics of powders. For the needs of pharmaceutical technology it is, however, necessary to specify better the conditions of its determination, above all in the selection of a suitable range of the dimension of evaluation („walk“) with regard to the largest dimension of the aggregates of powders.

        Key words: fractal dimension – powders – aggregates – elutriation – specific surface