Cisplatin and oleanolic acid Co-loaded pH-sensitive CaCO3 nanoparticles for synergistic chemotherapy.

Despite being one of the most potent anticancer agents, cisplatin (CDDP) clinical usage is limited owing to the acquired resistance and severe adverse effects including nephrotoxicity. The current work has offered a unique approach by designing a pH-sensitive calcium carbonate drug delivery system for CDDP and oleanolic acid (OA) co-delivery, with an enhanced tumor efficacy and reduced unwanted effects. Micro emulsion method was employed to generate calcium carbonate cores (CDDP encapsulated) followed by lipid coating along with the OA loading resulting in the generation of lipid-coated cisplatin/oleanolic acid calcium carbonate nanoparticles (CDDP/OA-LCC NPs). In vitro biological assays confirmed the synergistic apoptotic effect of CDDP and OA against HepG2 cells. It was further verified in vivo through the tumor-bearing nude mice model where NPs exhibited enhanced satisfactory antitumor efficacy in contrast to free drug solutions. In vivo pharmacokinetic study demonstrated that a remarkable long circulation time with a constant therapeutic concentration for both drugs could be achieved via this drug delivery system. In addition, the in vivo imaging study revealed that DiR-loaded NPs were concentrated more in tumors for a longer period of time as compared to other peritoneal tissues in tumor bearing mice, demonstrating the site specificity of the delivery system. On the other hand, hematoxylin and eosin (H&E) staining of Kunming mice kidney tissue sections revealed that OA greatly reduced CDDP induced nephrotoxicity in the formulation. Overall, these results confirmed that our pH-sensitive dual loaded drug delivery system offers a handy direction for effective and safer combination chemotherapy.