Krebs Cycle Intermediate-Modified Carbonate Apatite Nanoparticles Drastically Reduce Mouse Tumor Burden and Toxicity by Restricting Broad Tissue Distribution of Anticancer Drugs

The morphology, size, and surface area of nanoparticles (NPs), with the existence of functional groups on their surface, contribute to the drug binding affinity, distribution of the payload in different organs, and targeting of a particular tumor for exerting effective antitumor activity in vivo. However, the inherent chemical structure of NPs causing unpredictable biodistribution with a toxic outcome still poses a serious challenge in clinical chemotherapy. In this study, carbonate apatite (CA), citrate-modified CA (CMCA) NPs, and α-ketoglutaric acid-modified CA (α-KAMCA) NPs were employed as carriers of anticancer drugs for antitumor, pharmacokinetic, and toxicological analysis in a murine breast cancer model. The results demonstrated almost five-fold enhanced tumor regression in the cyclophosphamide (CYP)-loaded α-KAMCA NP-treated group compared to the group treated with CYP only. Also, NPs promoted much higher drug accumulation in blood and tumor in comparison with the drug injected without a carrier. In addition, doxorubicin (DOX)-loaded NPs exhibited less accumulation in the heart, indicating less potential myocardial toxicity in mice compared to free DOX. Our findings, thus, conclude that CA, CMCA, and α-KAMCA NPs extended the circulation half-life and enhanced the anticancer effect with reduced toxicity of conventional chemotherapeutics in healthy organs, signifying that they are promising drug delivery devices in breast cancer treatment.