Process parameters and morphology in amoxicillin micro and submicro particles generation by supercritical antisolvent precipitation

Continuous supercritical antisolvent precipitation (SAS) has been used to produce micro and sub-micro particles of amoxicillin. Liquid solutions of amoxicillin in N-methyl pyrrolidone (NMP) or dimethylsulfoxide (DMSO) have been continuously sprayed using supercritical CO2 as the antisolvent. When DMSO has been used, the precipitation of amoxicillin has been only partly successful and two different particle morphologies have been observed during the same experiment. When amoxicillin has been solubilized in NMP, spherical and non-agglomerated microparticles have been obtained by SAS with mean diameters ranging between 0.25 and 1.2 μm obtained at various precipitation temperatures and solute concentrations in the liquid solution. The effect of the ratio of CO2/liquid solution flow rates has also been studied.