The precision of dosing of powder drugs in piece dosage forms can be theoretically forecast by means of statistical principles of variability of random mixtures, the use of which for this purpose has been traditionally examined. The present critical review of the literature of the subject is primarily focused on random mixing of powder mixtures, their homogenity, volume dosing, and the use of a correlogram in the examination of nonrandom and segregated mixtures. The knowledge is useful both for the selection of a suitable particle size and for the verification of suitability of the employed parameters of mixing and the technological processing of the obtained mixture.

        Key words: powders – random mixture – homogenity – segregation – correlogram