Transfer Mechanism of Anthracycline Antibiotics and Their Ion Association with PAMAM Dendrimer at Liquid|Liquid Interfaces

The transfer reaction of anthracycline antibiotics, daunorubicin (DNR) and doxorubicin (DOX), was investigated at the water|1,2-dichloroethane (DCE) interface. Spectroelectrochemical analysis demonstrated significant changes in the transfer mechanism of anthracycline cations with a slight structural difference across the bare water|DCE interface and the biomimetic interface with a phospholipid layer. The facilitated ion transfer feature was found for both HDNR+ and HDOX+ at the biomimetic interface, where the adsorption process of HDOX+ was observed over a wide potential range at the aqueous side of the interface, that is, the polar headgroup region of the phospholipid layer. The molecular association between the carboxylate-terminated generation 3.5 polyamidoamine (G3.5 PAMAM) dendrimer and anthracycline derivatives occurred preferentially under neutral pH conditions. The negatively charged G3.5 PAMAM dendrimer induced positive shifts of the transfer potential of anthracycline cations at the water|DCE interface, indicating its ability as potential- and pH-responsive drug carriers.