A Supramolecular Assembly Formed by Heteroassociation of Ciprofloxacin and Norfloxacin in the Solid State: Co-Crystal Synthesis and Characterization

Crystal Growth and Design

American Chemical Society

Año: 2013 vol. 13 p. 1050 - 1050

1092-4221

n investigation on the interaction in the solid state of ciprofloxacin (CIP) and norfloxacin (NOR) was undertaken. A multicomponent molecular complex (COP) was obtained, which is composed of equimolar quantities of both compounds, according to TLC and 1H NMR data. As single-crystal X-ray analysis showed, COP crystallizes in the triclinic system, space group P(-1), with 4.86 water molecules per formula unit. The asymmetric unit contains three independent molecules (A, B and C) with contributions of both CIP and NOR. At the molecule A site, the occurrence is about 37% (CIP), 63% (NOR); at the B site, there is predominantly CIP (70%); and at the C site the occurrence is about 43% (CIP) and 57% (NOR), yielding an overall 1:1 CIP-NOR ratio in the crystal. TG data evidenced a one-step loss of solvent (about 18% per COP molecule) below 110 °C, confirming the presence of water molecules. The driving force of CIP and NOR interaction, resulting in a supramolecular structure with water molecules