Provided herein is rasagiline mesylate having a 90 volume-percent of the particles (D90) with a size of about 600 microns to about 1500 microns, and a process for the preparation thereof. Provided also herein are pharmaceutical compositions comprising rasagiline mesylate particles having a particle size which is suitable for homogeneous distribution of the drug substance in a tablet blend, in particular 90 volume-percent of the particles (D90) have a size of about 255 microns to about 1500 microns, and a process the preparation thereof.
