During the antisolvent crystallization of L-histidine from aqueous solution with the antisolvent ethanol, the polymorphic
fraction of the metastable polymorph B increased with increasing supersaturation ratio. For supersaturation ratio SA e 2.0, a mixture
of the stable polymorph A and the metastable polymorph B was obtained, while for high supersaturation, SA g 2.3, only form B was
observed.