Within the production technology of the phenoximethyl-penicillinic acid (in the following: PMPA) the influence of each of the parameters of precipitation on particle size distribution were examined. Matching the tangent hyperbolic distribution function with the experimental data it can be seen that the distributions of granular products obtained under various experimental conditions can be well described with the help of the tangent hyperbolic distribution function. The average and minimum size of the particles, as well as the standard deviation and relative standard deviation were determined.