Improvement in the Anticancer Activity of 6-Mercaptopurine via Combination with Bismuth(III)

6-Mercaptopurine (6-MP) is a clinically important antitumor drug and its commercially available form is provided as monohydrate, belonging to biopharmaceuticals classification system (BCS) class II category. The combination of bismuth(III) (Bi(III)) with 6-MP was proved to significantly improve the anticancer activity of 6-MP, leading to the discovery of a new amorphous complex ([Bi(MP)3(NO3)2]NO3). The prepared [Bi(MP)3(NO3)2]NO3 was characterized by the matrix assisted laser desorption-ionization time-of-flight (MALDI-TOF)-MS, etc. Noticeably, according to the in vitro evaluations of cytotoxicity, cellular apoptotic, colony formation as well as cell migration, the anticancer activity of amorphous [Bi(MP)3(NO3)2]NO3 was found to be of high therapeutic effect over 6-MP.