Two-dimensional 13C–1H heteronuclear correlation NMR spectroscopic studies for the inclusion complex of cyclomaltoheptaose (β-cyclodextrin) with a new Helicobacter pylori eradicating agent (TG44) in the amorphous state Original Research Article

The interaction of a newly developed Helicobacter pylori eradicating agent (TG44, 4-methylbenzyl-4′-[trans-4-(guanidinomethyl)cyclohexylcarbonyloxy]-biphenyl-4-carboxlylate monohydrochloride) with cyclomaltoheptaose (β-cyclodextrin, β-CyD) in the solid state was studied by high-speed frequency-switched Lee-Goldburg (FSLG) 13C–1H heteronuclear correlation (HETCOR) NMR experiments. The TG44/β-CyD solid complex in a 1:1 stoichiometry was prepared by the grinding method. Powder X-ray diffractometry confirmed that the complex is in an amorphous state. The solid-state 13C signals of TG44 and β-CyD were significantly broadened by the complexation. As the temperature increased, the 13C signals of the aromatic moieties of TG44 were insignificantly influenced, whereas those of the cyclohexyl moiety be