title: Ferricenium complexes: a new type of water-soluble antitumor agent.
abstract: The antitumor activity of a series of iron complexes, i.e., of ferrocene [Cp2Fe], of tetrachloroferrates(III) [R4N]+[FeCl4]-, and of ferricenium complexes [Cp2Fe]+X- (X- = [FeCl4]-, 1/2 [Cl3FeOFeCl3]2-, [H5Mo7O24]- X 2H2O, [2,4,6-(NO2)3C6H2O]-, or [CCl3COO]- X 2 CCl3COOH) was investigated against EAT in CF1 mice. Whereas ferrocene and the ammonium tetrachloroferrates(III) did not show recognizable tumor-inhibiting activity, such activity was exhibited by the water-soluble, salt-like ferricenium complexes; the best antineoplastic properties, with optimum cure rates of 100%, were found for ferricenium picrate and ferricenium trichloroacetate. The ferricenium compounds are the first iron complexes for which antineoplastic activity has now been shown. They represent a new type of antitumor agent insofar as they differ fundamentally from known inorganic and organometallic antitumor agents (a) by their ionic, salt-like character, which is responsible for their high water solubility, and (b) by the absence of a cis-dihalometal moiety; this moiety has been recognized as important for the intracellular action of other known inorganic cytostatics.
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents; D002286:Carcinoma, Ehrlich Tumor / Q000188:drug therapy; D055598:Chemical Phenomena; D002621:Chemistry; D004305:Dose-Response Relationship, Drug; D005260:Female; D005296:Ferrous Compounds / Q000494:pharmacology; D000075163:Metallocenes; D051379:Mice; D009942:Organometallic Compounds / Q000494:pharmacology; D012995:Solubility
chemical_list: D000970:Antineoplastic Agents; D005296:Ferrous Compounds; D000075163:Metallocenes; D009942:Organometallic Compounds; C004998:ferrocene