Preliminary investigations into the behavior of urea: succinic acid co-crystals on scale-up by batch crystallizations

Abstract: Crystallization is an important method used for purification and in
production of solid form of pharmaceutical products. Screening of urea and
succinic acid in different organic solvents was conducted to identify the
most suitable solvent for crystallization process.
The screening process produced isopropanol as the most suitable solvent.
Cooling crystallization was carried out using Julabo Easy Temp software for
temperature control with 100Pt IKA temperature sensor inserted in the
crystallizer for temperature monitoring. Solubility studies of urea-
succinic acid co-crystals were conducted, using an HPLC method, to find a
cooling profile so as to determine the effects of process parameters on the
quality of products obtained. The solubility of urea-succinate co-
crystals was found to be temperature dependent because at a fixed stirring
rate, solubility decreases with decrease in temperature . DSC, PXRD, and
Raman data confirmed the formation and stability of urea-succinate co-
crystals on scale-up. The process parameters of stirring rate, cooling rate
and temperature had no significant influence on urea-succinic acid co-
crystals on scale-up.