Recrystallization of salicylamide using a batch supercritical antisolvent process

Recrystallization of the nonsteroidal anti-inflammatory drug salicylamide was investigated using a batch supercritical antisolvent (SAS) precipitation process. Carbon dioxide was used as the antisolvent, and acetone, ethanol and ethyl acetate were used as solvents. Particle morphology determined by SEM showed that particles with a regular shape were obtained from the SAS process. The crystal structure analyzed by XRD showed that the intensities of specific peaks were modified. No decomposition or deterioration was confirmed by DSC measurements where the melting temperature remained the same after SAS recrystallization. The effects of process parameters were investigated with acetone as the solvent. At a higher pressure of 110 bar, a higher saturation concentration of 90 %, and a lower temperature of 293 K, the length of the rectangular particles decreased to 50 μm. This showed a significant change from the irregular and broken particle shapes with particle sizes up to 200 μm before processing by SAS.