2D homonuclear and heteronuclear correlation NMR experiments in solid state applied to a new pharmaceutical compound

Y. GARRO LINCK; A. K. CHATTAH; C. B. ROMAÑUK; M. E. OLIVERA; R. H. MANZO; S CUFFINI; R. GRAF; G. A. MONTI; H. W. SPIESS

Gotemburgo, Suecia

Congreso; EUROMAR 2009; 2009

EUROMAR

Advanced solid states nuclear magnetic resonance (NMR) techniques have been used to study a new pharmaceutical compound, the ciprofloxacin saccharinate (CIP-SAC). This compound has been previously reported and fully characterized with solid state techniques (IR, DSC, XRD, 13C CP-MAS NMR). This saccharinate evidences polymorphism presenting two well distinguished solid forms CIP-SAC (I) and (II). In this work we have performed the 2D 13C-1H heteronuclear correlation experiment (REPT-HSQC and HETCOR) which allowed the complete assignment of the resolved 1H solid state spectrum. These data were complemented with double quantum MAS experiment (BABA pulse sequence) to identify 1H-1H connectivities, hydrogen bondings and dipolar proximities. The zwitterionic character of ciprofloxacin and its derivative was identified. Further information about inter and intra molecular interactions in both solid forms of the new saccharinate was obtained. Differences and similarities in the structures of the different solid forms have also been established and supported with single crystal XR diffraction data obtained for the form II.