title: Pharmacokinetics of cobalt chloride and cobalt-protoporphyrin.
abstract: A comparison of the pharmacokinetics of the trace element cobalt and the protoporphyrin chelate of this metal, cobalt-protoporphyrin, was conducted in male Sprague-Dawley rats. Following subcutaneous treatment (250 mumol/kg body weight), cobalt was found predominantly (> 95%) in plasma, from which it was rapidly eliminated (t1/2 approximately 25 hr). Cobalt-protoporphyrin, also found almost exclusively in plasma (> 95%), exhibited a much slower elimination rate (approximately 3 days) in comparison to the noncomplexed metal. Four weeks after dosing with either inorganic cobalt or cobalt-protoporphyrin, tissue levels of cobalt were measured by graphite furnace atomic absorption spectroscopy. The kidney retained the highest levels of cobalt (1 and 4 micrograms/g dry tissue weight, respectively), although in cobalt-protoporphyrin-treated rats, elevated levels of cobalt (1.5 micrograms/g) were still observed in the spleen, gonads, lung, and thymus up to 4 weeks posttreatment. These differences in pharmacokinetics between inorganic cobalt and cobalt-protoporphyrin are discussed in terms of the differing biological properties exhibited by the metal in its different chemical associations.
authors.affiliation: School of Pharmacy, University of Connecticut, Storrs 06268.
authors.forename: D W
authors.initials: DW
authors.lastname: Rosenberg
mesh_terms: D000818:Animals; D003035:Cobalt / Q000097:blood / Q000493:pharmacokinetics*; D007279:Injections, Subcutaneous; D008297:Male; D011524:Protoporphyrins / Q000097:blood / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
chemical_list: D011524:Protoporphyrins; D003035:Cobalt; C007095:cobaltiprotoporphyrin; C018021:cobaltous chloride