Carboplatin decomposition in aqueous solution with chloride ions monitoredby X-ray absorption spectroscopy

Carboplatin aqueous solutions, with chloride ions added at different concen trations, were studied by X-ray absorption spectroscopy (XAS). The comparis on of solid and solution spectra shows that carboplatin and cisplatin spect ra are strongly different, and that the carboplatin ligands induce a specif ic structure of the spectrum, conserved in solution. Hence, it is possible to study by XAS the evolution of carboplatin in solution. This study shows that carboplatin is the major compound present in solution, even after 15 d ays, in neutral solutions with chloride concentration less than 9%, exposed to light or not. On the contrary, with high chloride concentrations (18%) or in acidic solutions (0.1 M HCl), the carboplatin is chlorolysed, the evo lution of the solution composition can be followed by XAS and cisplatin for mation is evidenced.