Enhanced tumor delivery and antitumor response of doxorubicin-loaded albumin nanoparticles formulated based on a Schiff base

A novel method was developed here to prepare albumin-based nanoparticles (NPs) for improving the therapeutic and safety profiles of chemotherapeutic agents. This approach involved crosslinking bovine serum albumin (BSA) using a Schiff base-containing vanillin, into NPs and loading doxorubicin (DOX) into the NPs by incubation. The resultant NPs (DOX-BSA-V-NPs) displayed a particle size of 100.5±1.3 nm with a zeta potential of −23.05±1.45 mV and also showed high drug-loading efficiency and excellent stability with respect to storage and temperature. The encapsulation of DOX into the BSA-V-NPs was confirmed by dynamic scanning calorimetry and Raman spectroscopy. DOX-BSA-V-NPs exhibited a significantly faster DOX release at pH 6.5 than pH 7.4, as well as in a solution with a higher glutathione concentration. In vitro studies showed that the cellular uptake of DOX-BSA-V-NPs was time-dependent, concentration-dependent, and faster than free DOX, while the cytotoxicity of DOX-BSA-V-NPs (IC(50) value of 3.693 μg/mL) was superior to free DOX (IC(50) value of 4.007 μg/mL). More importantly, DOX-BSA-V-NPs showed a longer mean survival time of 24.83 days, a higher tumor inhibition rate of 56.66%, and a decreased distribution in the heart than other DOX formulations in animal studies using a tumor xenograft model. Thus, the vanillin-based albumin NPs were shown here to be a promising carrier for tumor-targeted delivery of chemotherapeutic agents and, thus, should be further studied.