Determination of a new oral iron chelator, ICL670, and its iron complex inplasma by high-performance liquid chromatography and ultraviolet detection

ICL670 is a representative of a new class of orally active tridentate selec tive iron chelators. Two molecules of ICL670 are required to form a complet e hexacoordinate chelate Fe-[ICL670](2) with one ferric iron. A simple and rapid HPLC-UV method for the separate determination of ICL670 and Fe-[ICL67 0](2) in the plasma of iron-overloaded patients is described. Plasma sample s were prepared as rapidly as possible, the tubes being kept at 4 degreesC. Plasma proteins were precipitated with methanol. The supernatant was dilut ed with water and placed on the refrigerated sample rack of an autosampler before injection. The chromatographic separations were achieved on an Allti ma C-18 column using 0.05 M Na2HPO4 and 0.01 M tetrabutylammonium hydrogen sulfate-acetonitrile-methanol (41:9:50, v/v/v) as mobile phase. The analyte s were detected at 295 nm. Calibration and quality control samples were pre pared in normal human plasma. The mean accuracy (n=6) over the entire inves tigated concentration range 0.25-20 mug/ml ranged from 91 to 109% with a co efficient of variation (C.V.) from 4 to 8% for ICL670, and from 95 to 105% with a C.V. from 2 to 20% for the iron complex. The dissociation of the com plex during analysis was shown to be marginal. The iron removal from plasma of iron-overloaded patients by free ICL670 during analysis was low. The in vitro iron transfer from the iron pools of iron-overloaded plasma onto ICL 670 was shown to be a slow process. (C) 2001 Elsevier Science B.V. All righ ts reserved.