Table of Contents
Metal-Based Drugs
Volume 7, Issue 4, Pages 195-200

Biological Properties of IRIM, the Iridium(III) Analogue of (Imidazolium (Bisimidazole) Tetrachlororuthenate) (ICR)

1CIRCMSB, Unit of Florence, via Gino Capponi 7, Florence I-50121, Italy
2Department of Chemistry, University of Florence, Florence I-50121, Italy
3Istituto di Strutturistica Chimica “G. Gia6omello” Area della Ricerca di Roma, CNR CP10, Monterotondo Stazione, Rome I-00016, Italy
4Fondazione Callerio, via A. Fleming 22, Trieste 31 I-34127, Italy

Received 23 June 2000; Accepted 22 August 2000

Copyright © 2000 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Some biological aspects of the new complex imidazolium bisimidazole tetrachloro iridate(III)-IRIM- the iridium(III) analogue of ICR, were considered. More in detail the conformational effects produced by IRIM on DNA and the cytotoxic properties of IRIM on some selected human cell lines were measured. Dialysis experiments and DNA thermal denaturation studies are suggestive of poor binding of IRIM to DNA; formation of interstrand crosslinks is not observed. In any case CD measurements suggest that addition of increasing amounts of IRIM to calf thymus DNA results into significant spectral changes, that are diagnostic of a direct interaction with DNA. A number of experiments carried out on the A2780 human ovarian carcinoma, B16 murine melanoma, MCF7 and TS mammary adenocarcinoma tumor cell lines strongly point out that IRIM does not exhibit significant growth inhibition effects within the concentration range 10-4-10-6 M. It is suggested that the lower biological effects of IRIM compared to ICR are a consequence of the larger kinetic inertness of the iridium(III) center with respect to ruthenium(III).