Low pressure phases

A metastable form of γ-aminobutyric acid has been prepared by sublimation under vacuum. A theoretical unary phase diagram has been deduce from experimental thermal analysis. Aqueous solution of γ-aminobutyric acid (Gaba) prepared from commercial product (monoclinic) does not cross blood–brain barrier after intra peritoneal administration to mice, hence it displays no anticonvulsion activity. Therefore, we developed a polymorphic form, the solution of which presents such activity. In the present paper the preparation and the physico-chemical properties are reported.