2022 Volume 55 Issue 12 Pages 365-369
In pharmaceutical ingredients production, crystallizing desired polymorph selectively is important. Particularly, manufacturing of unstable or metastable polymorph crystalline products are crucial in pharmaceutical ingredients due to its high bioavailability. In the case of glycine, β-form is the most unstable form and has been investigated about stably crystallizing method in batch operations although it has not been researched about the methods of stably crystallizing in continuous operations. We have developed a continuous flow crystallizer that can generate strong micro mixing effect at reaction zone by utilizing Taylor vortex. We carried out anti-solvent crystallization of glycine to look over reaction conditions that can crystallize β-form stably. We also carried out experiments with varying ratio of glycine aqueous solution and ethanol, inner cylinder rotation speed and residence time. β-form glycine can be obtained over 65% ethanol mass ratio, high inner cylinder rotation speed and long residence time promotes crystallize β-form.
