SIMULTANEOUS DETERMINATION OF HYDROXOCOBALAMIN AND ITS CYANIDE COMPLEX CYANOCOBALAMIN IN HUMAN PLASMA BY HIGHPERFORMANCE LIQUID-CHROMATOGRAPHY - APPLICATION TO PHARMACOKINETIC STUDIES AFTER HIGH-DOSE HYDROXOCOBALAMIN AS AN ANTIDOTE FOR SEVERE CYANIDE POISONING

Hydroxocobalamin (OHCbl) is a powerful antidote for cyanide poisoning, via the formation of non-toxic cyanocobalamin (CNCbl), Plasmatic cobalamins were measured at 361 nm, after enrichment and purification on a short C-18 precolumn (1% acetic acid; 1 ml min(-1) 2 min), by back-flush elution on a C-18 ODS-2 column [0.1 M sodium dihydrogenphosphate-methanol (63:27, v/v) (pH 4.0); 0.80 ml min(-1)]. The precision was 3.21 and 3.54% for 10 mu M OHCbl and CNCbl, respectively. The method was used to study the pharmacokinetics of OHCbl and the formed CNCbl in severely poisoned patients.