Adsorption of the Pt II Anticancer Drug Carboplatin by Mesoporous Silica

MCM‐41, a mesoporous silica nanomaterial with a high surface area for adsorption of small molecules, is a potential new type of delivery vehicle for therapeutic and diagnostic agents. In this report, we show that MCM‐41 adsorbs the front‐line anticancer drug carboplatin, [Pt(CBDCA‐ O , O′ )(NH 3 ) 2 ] (CBDCA=cyclobutane‐1,1‐dicarboxylate; 1 ), which is used to treat ovarian, lung, and other types of cancer. UV/Visible difference absorption spectroscopy shows that MCM‐41 adsorbs 1.8±0.2% of its own weight of carboplatin after a 24 h exposure to 26.9 m M drug in H 2 O. The pseudo ‐first‐order rate constant for adsorption of carboplatin by MCM‐41, measured using [ 1 H, 15 N] heteronuclear single quantum coherence (HSQC) NMR, and 15 N‐labeled carboplatin is k 1 =2.92±2.17×10 −6  s −1 at ca. 25°.