Synthesis, Characterization and In Vitro Cytotoxic Assay of La(III) Complex with Chlorambucil

This work studies the synthesis of complexes using chlorambucil (La-CLA) as a ligand and lanthanum as a metallic center, in order to enhance their biological activities. The compounds produced were characterized by infrared spectroscopy and 13C and 1H nuclear magnetic resonance; the results obtained indicate that coordination bonds formed between the ligands and that La3+ was present in a bidentate way through carboxylic groups in the complexes. Elemental and thermogravimetric analyses indicate that the stoichiometry obtained for chlorambucil complexes was a 2:1 ligand:metal ratio. The anticancer activity assays indicated that the La-CLA complex showed better activity than the ligands against the cell lines K562 (Chronic Myeloid Leukemia), HT-29 (Colorectal Cancer), Caco 2 (Human Colorectal Adenocarcinoma) and B16-F10 (Murine Melanoma), with GI50 values in the range of 0.31–31.86 μM. The La-CLA complex showed a selectivity index (SI) equal to 15.64 for the K562 cell line with respect to normal J774 cells (murine macrophages).