CBD loaded microparticles as a potential formulation to improve paclitaxel and doxorubicin-based chemotherapy in breast cancer.

Cannabidiol (CBD) has emerged as a potential agent for breast cancer management. In this work, the potential use of cannabidiol in solution (CBDsol) and encapsulated in polymeric microparticles when combined with paclitaxel (PTX) and doxorubicin (DOX) in breast cancer treatment has been evaluated for the first time using MCF-7 and MDA-MB-231 cells. CBDsol, previously administered at suboptimal concentrations (cell death < 10%), enhanced the PTX and DOX effect in both breast cancer cells. The co-administration of CBDsol and PTX or DOX showed a synergistic effect. PLGA-502 was selected as the most suitable polymer to develop CBD-loaded microparticles. The developed formulation (CBD-Mps) was effective as monotherapy, showing extended antiproliferative activity for at least 10 days, and when combined with PTX or DOX. In fact, the use of CBD-Mps allows the combination of both, pre and co-administration strategies, with a single administration, also showing a significant increase in PTX and DOX antiproliferative activity. Finally, the anticancer effect of both CBDsol and CBD-Mps as monotherapy or in combination with PTX was also confirmed in ovo, usingMDA-MB-231-derived tumours. This data evidences the promising inclusion of CBD in conventional breast cancer chemotherapy and the use of CBD-Mps for the extended release of this cannabinoid, optimising the effect of the chemotherapeutic agents.