Synthesis and characterization of a new bile acid and platinum(II) complex with cytostatic activity

With a view to using bile acids as shuttles for delivering platinum-related cytostatic drugs to the liver, a cholylglycine(CG)-derivative of platinum(II) has been synthesized. The complex, named Bamet-H2, was characterized by elemental analysis, FT-IR, NMR, FAB-MS, and UV spectroscopy. The results indicate the following composition: C52H84N2O12ClNa Pt(II). Conductivity data suggest that the complex behaves as a sodium salt (1:1) of a complex of Pt(II) bound to one cl-, one bidentate CG moiety, and another monodentate CG moiety, i.e., Na[Pt(CG-O,N)(CG-O)Cl]. The compound is highly soluble (up to 10 mM) in water, ethanol, methanol, DMF, and DMSO. Bamet-H2 was stable in solution (either water or 150 mM NaCl solution), as measured by HPLC, up to 24 h. At this time, more than 90% of the platinum present in water or saline solutions was found to be Bamet-H2. Cytostatic activity against L1210 murine leukemia cells was found. This characteristic was stronger against rat hepatocytes in primary culture. Isolated in situ rat livers were perfused for 40 min with a recirculating medium containing 1 microM Bamet-H2, CG, or cisplatin. Uptake and excretion into bile were much greater for Bamet-H2 than for cisplatin, but less than for CG. Liver content was higher for Bamet-H2 than for cisplatin or CG. The results point to the potential usefulness of Bamet-H2 in the antitumoral therapy of neoplasias derived from liver parenchymal cells.