Hydroxocobalamin
Hydroxocobalamin, a vitamin. Cobalamin with a hydroxyl ligand at the central cobalt. Binds transcobalamin II more tightly than… Intramuscular half-life 26 h.
Cobalamin with a hydroxyl ligand at the central cobalt. Binds transcobalamin II more tightly than cyanocobalamin, giving a substantially longer plasma residence time (effective t½ weeks to months after IM). Converted intracellularly to methylcobalamin and adenosylcobalamin via the canonical MMACHC/MMADHC trafficking pathway. Also acts as a potent cyanide chelator — forms cyanocobalamin which is renally excreted, hence its Rx role (Cyanokit) in smoke-inhalation poisoning.
PK: THE CITED ABSTRACT STATES THE VOLUME AND THE RECORD STORED THE SOLVER DEFAULT INSTEAD. Verbatim: "the elimination half-life 26.2 +/- 2.7 h. The apparent volume of distribution is 0.45 +/- 0.03 L/kg" — the half-life was taken and the volume beside it was not, leaving 0.5 L/kg standing in for a measured 0.45. Eleven percent, and free. A CAVEAT THE ABSTRACT RAISES ITSELF: the cohort is eleven smoke-inhalation victims with cyanide exposure, and it warns that this "elimination half-life in these cyanide-exposed patients far exceeds those found in previous studies of dogs and minimally-exposed humans" — so the record describes the antidotal setting, not routine supplementation.
Pharmacokinetics
- Intramuscular — t½ 26.2 h · F 100% · Vd 31.5 L
- IV — t½ 26.2 h · F 100% · Vd 31.5 L
Related compounds
- Cyanocobalamin — synergistic
- Methylcobalamin — synergistic
Sources: PMID:25117994