Crystallization is widely used in the pharmaceutical and chemical industries as one of the simplest and cheapest method of obtaining high purity solids. The method of crystallization and the conditions under which crystallization is carried out greatly affect the final properties of the crystal, such as the shape and form of the crystal, purity, particle size distribution, etc. Cocrystals are crystalline material of significant interest in the pharmaceutical industry, allowing to change the physico-chemical properties of the active substance (API) without changing their molecular structures. In this paper, the process of crystallization of cocrystals of the tosylate salt of the active substance with mandelic acid was investigated and the batch crystallization process was optimized. The influence of the additional set of hydrodynamic conditions on the chemical and polymorphic purity of crystals, particle size distribution and process efficiency was determined. The shape of the crystal was monitored by a scanning electron microscope and a particle size distribution was determined by laser diffraction. Linear particle size distribution was also monitored using a focused beam reflection probe. The crystalline form of the obtained cocrystals of the tosylate salt of the active substance was determined by powder X-ray diffraction. Based on all the obtained results, the most optimal API crystallization process was selected.