GABA-Controlled Synthesis of the Metastable Polymorphic Form and Crystallization Behavior with a Chiral Malic Acid

The controlled pH-based crystallization approach with acetic acid to the pharmaceutical interesting metastable polymorph H of the API gamma-aminobutyric acid (GABA), which is hitherto accessible by sublimation under reduced pressure and high temperature, is described. Furthermore, the synthesis and single crystal characterization of a nonhydrated chiral [GABA-H] [malate] compound is presented.