Drug-loaded nanoemulsion as positive control is an alternative to DMSO solutions for in vitro evaluation of curcumin delivery to MCF-7 cells.

BACKGROUND: In vitro evaluation of toxicity and/or efficacy of nanostructured drug delivery systems involves the uses of different controls, including positive and negative controls, as well as a solution or dispersion of the drug in water. One of the most frequently solvent used to dilute poorly water soluble drugs to in vitro tests are dimethylsulfoxide (DMSO). However, its different specific surface area and different diffusion coefficients could make the comparative effects difficult. We proposed that a solvent-free dispersions having similar specific surface area could be a better control than drug in solution against cell lines.

METHODS: We evaluate the effect of curcumin-loaded lipid-core nanocapsules, curcumin-loaded nanoemulsion and curcumin DMSO-water solution on viability and colony forming efficiency of human breast cancer cell line, MCF7.

RESULTS: The cytotoxic effect of nanocapsules at 24-72h was similar to nanoemulsion and lower than drug solution. However, the nanocapsules had a superior anticancer activity when long periods (10days) were evaluated, which highlight the sustained drug release by nanocapsules.

CONCLUSIONS: Our results showed a superior anticancer activity of curcumin-loaded lipid-core nanocapsules compared to curcumin-loaded nanoemulsion and curcumin dissolved in DMSO in long exposition time assay, wihch is not observed in short exposition time assays like MTT. When a poorly water-soluble drug is under investigation, the nanoemulsion prepared with the same compounds of the nanocapsules, except the polymer, could be a better control than DMSO-solution of drug.