Antitumor titanium compounds.

Most anticancer titanium compounds act against tumors in the gastrointestinal tract. Activity towards breast, lung and skin (melanoma) cancers is shown by some as well. Among their appealing properties is that they do not show common side effects of widely used cytostatic agents such as emesis, alopecia or bone marrow impairment. These features make titanium compounds interesting for combined therapy and further study. This review focuses on two drugs that reached clinical trials, namely, titanocene dichloride and budotitane. We try to integrate the biological fate of the related Ti-cyclopentadienyl and Ti-beta-diketonato families of drugs, delineating the structure-activity relationship. We also discuss novel related species with increased solubility for improved drug delivery and some potentially useful polynuclear compounds.