A F-19 NMR-STUDY OF LOMEFLOXACIN IN HUMAN ERYTHROCYTES AND ITS INTERACTION WITH HEMOGLOBIN

F-19 NMR spectroscopy of a model fluoroquinolone, lomefloxacin, in an erythrocyte suspension showed separate resonances for the intra- and e xtra-cellular compartments. The intra-cellular peak revealed significa nt line broadening of the fluorine signals of lomefloxacin. Line broad ening also occurred in the presence of oxyhemoglobin (HbO(2)), hematin , globin and iron. This evidence indicated that lomefloxacin interacte d with these compounds; however, ultrafiltration experiments indicated that there was only weak binding (5%) of lomefloxacin to HbO(2). F-19 and P-31 NMR spectroscopy revealed that lomefloxacin may compete with 2,3-diphosphoglycerate for its binding site on HbO(2). An apparent pa rtition coefficient of 1.90 +/- 0.15 was observed for lomefloxacin in human erythrocytes, utilizing LC analysis.