Pharmacological compositions, and methods for administration, of the type employing an iron oxide complex with a polyol or polyether. The methods of administration may comprise parenteral administration of an effective dose of the complex formulated in a biocompatible liquid delivered at a rate of from about 1 mL/sec to less than 1 mL/min and wherein upon administration the complex provides minimal detectable free iron in a subject, and minimal incidence of anaphylaxis. The pharmacological compositions are of the type employing a polyol or polyether iron oxide complex, which, upon parenteral administration to a subject, are substantially immunosilent, provide minimal anaphylaxis and minimal free iron, and undergo minimal dissolution in vivo.