β-Cyclodextrin inclusion complexes of Mg2+ and Ca2+ salts of meclofenamic acid:: Preparation and structural characterisation

The magnesium and calcium salts of the non-steroidal anti-inflammatory drug meclofenamic acid (2-[(2,6-dichloro-3-methylphenyl)amino]benzoic acid) were prepared and complexed with beta-cyclodextrin (beta-CD) to yield inclusion complexes with the compositions beta-CD-hemimagnesium meclofenamate center dot 16.8H(2)O (1) and beta-CD-hemicalcium meclofenamate center dot 16.5H(2)O (2). These complexes were investigated by thermal analysis techniques, elemental analysis, powder X-ray diffraction (PXRD) and single crystal X-ray diffraction at 113 K. The complexes yielded PXRD traces that closely matched that of the known complex beta-CD-sodium meclofenamate center dot 16H(2)O (3), indicating isostructurality among 1-3, reflected in very close similarities in the modes of inclusion of the anion in beta-CD. However, the locations and coordination environments of the Mg2+, Ca2+ and Na+ ions differ significantly in the respective crystals.