TOXIC EFFECT OF VANADIUM

Vanadium is toxic both as a cation and as an anion [15]. The toxicity of vanadium has been found to be high when it is given intravenous, low when it is orally administered, and intermediate in the case of respiratory exposure. Toxicity as observed by weight lose, poor appetite, vomiting and diarrhea has been associated with ingestion of vanadium compounds therefore the therapeutic index of some vanadium complexes can be quit narrow [16]. Recent efforts focused on identifying vanadium compounds with increased therapeutic potency and decreased toxicity. The recent successes achieved on transition metal complexes having organic ligands suggest that modification of the metal ion on combining with organic ligands not only increases efficacy but also decreases toxicity [17]. V(III) is readily oxidized to V(IV) and V(V) at physiological pH and V(IV) is lees toxic than V(V).