title: Polymorphs of gabapentin.
abstract: Gabapentin [or 1-(aminomethyl)cyclohexaneacetic acid], C(9)H(17)NO(2), exists as a zwitterion [1-(ammoniomethyl)cyclohexaneacetate] in the solid state. The crystal structures and bonding networks of two new monoclinic polymorphs (beta-gabapentin and gamma-gabapentin) are studied and compared with a previously reported gabapentin polymorph [alpha-gabapentin: Ibers (2001). Acta Cryst. C57, 641-643]. All three polymorphs have extensive networks of hydrogen bonds between the NH(3)(+) and COO(-) groups of neighbouring molecules. In beta-gabapentin, there is an additional weak intramolecular hydrogen bond.
authors.affiliation: Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits 2050, South Africa.
authors.forename: Hayley A
authors.initials: HA
authors.lastname: Reece
authors.forename: Demetrius C
authors.initials: DC
authors.lastname: Levendis
mesh_terms: D000588:Amines / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003509:Cyclohexanecarboxylic Acids / Q000737:chemistry*; D019281:Dimerization; D000077206:Gabapentin; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism; D005680:gamma-Aminobutyric Acid / Q000737:chemistry*
chemical_list: D000588:Amines; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin