In this thesis, wet tumble granulation is scrutinized as a potential process technology for formulation of pharmaceutical substance, saccharose in order to produce tablets with good end-use properties in a tabletting process technology. Batch granulation tests were performed by tumbling of powder substance in process geometry of inclined disc in a lab-scale. Air and binder, water solution of polyvinylpyrrolidone whose droplet population is added by spraying, are additionally used in physical conversion of a substance. Study of the granulation phenomenon in a lab-scale is focused towards detection of process conditions and binder composition that will synergically drive micro- and meso-scale events in a favourable and aimed way and therewith result in a collective of stable enlarged entities, saccharose granules. Detected changes of the property of a group of entities, particle size distribution (PSD) with respect to granulation time point to the extent of physical conversion of pharmaceutical substance within granulation process. Process of underlying conversion of a substance is modelled with mechanistic approach using population balance. Such modelling approach in this thesis implies testing the applicability of a 1-D discretized population balance with Size-Independent Kernel (SIK) coalescence model for simulation of real temporal changes of saccharose PSD. Used approach indicates the contributions of underlying mechanisms in the granulation process. Optimization method that connotes minimizing the overall sum of squared errors is used for estimation of characteristic process parameter, coalescence rate constant. Thus, kinetic of physical conversion of saccharose in a stochastic environment of an inclined disc is quantified.