DISCLOSED HEREIN ARE NEW SALTS AND POLYMORPHS OF DESAZADESFERRITHIOCIN POLYETHER (DADFT-PE) ANALOGUES, AS WELL AS PHARMACEUTICAL COMPOSITIONS COMPRISING THEM AND THEIR APPLICATION AS METAL CHELATION AGENTS FOR THE TREATMENT OF DISEASE. METHODS OF CHELATION OF IRON AND OTHER METALS IN A HUMAN OR ANIMAL SUBJECT ARE ALSO PROVIDED FOR THE TREATMENT OF METAL OVERLOAD AND TOXICITY.