A combination of cannabidiol (CBD) and the chemotherapy drug epirubicin delivered through a nanoparticle-based carrier showed significantly greater activity against human ovarian cancer cells than epirubicin alone, according to a study published today.
Published in Nanotechnology, Science and Applications, the study examined a drug-delivery system using colloidal hydroxyapatite, or cHAp, to simultaneously carry CBD and epirubicin. Researchers tested the formulation against SKOV-3 human ovarian carcinoma cells.
The CBD-epirubicin formulation produced substantially greater reductions in cancer-cell viability than free epirubicin.
After 24 hours, cells treated with the combined formulation had viability levels 15% to 30% lower than cells treated with epirubicin alone, depending on the concentration. The effect became more pronounced with longer exposure.
After 72 hours, the CBD-epirubicin formulation reduced cell viability by more than 80% even at the lowest concentration tested. At the highest concentration of 3 micrograms per milliliter, cell viability fell to just 8%.
Researchers also performed a combination analysis to determine whether CBD and epirubicin were simply producing additive effects or interacting synergistically. The calculated combination index was 0.03077, well below the threshold of 1 used to indicate synergy.
“The cHAp_CBD_Epi conjugate demonstrated markedly enhanced cytotoxicity compared to free EPI,” researchers said.
CBD on its own showed limited cytotoxicity at the concentrations examined, while unmodified hydroxyapatite had little effect on cell viability. The findings indicate that the increased activity resulted from the combined drug-delivery system rather than the carrier itself.
Researchers also found that the formulation was stable and continuously released epirubicin, reaching a concentration of approximately 2 micrograms per milliliter after 24 hours.
The authors said the findings support further investigation of hydroxyapatite as a platform for delivering CBD alongside conventional cancer drugs.
However, the research was conducted entirely in vitro. The treatment has not been tested in animals or humans, and researchers said additional studies are needed to determine how the carrier is distributed, broken down and cleared in living organisms before clinical applications can be considered.
