In vitro investigations on the toxicity induced by tamoxifen and tamoxifen-loaded solid lipid nanoparticles on two breast cancer cell types

Objectives: Colloidal drug delivery system, solid lipid nanoparticles (SLNs), helps to increase the solubility of the drug and its oral bioavailability. Methods: Tamoxifen (TAM) as a nonsteroidal antiestrogen drug was formulated in SLN and an in vitro study was conducted to determine the cytotoxicity effect of TAM-loaded SLNs on human breast cancer cell lines MCF-7 (estrogen receptor-positive) and MDA-MB231 (estrogen receptor-negative) cells. The cytotoxicity was measured by (3-(4, 5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT assay). Results: The results showed that tamoxifen-loaded SLNs has an equally efficient cytotoxic activity against MCF-7 and MDA-MB231 cells, compared with free tamoxifen, and the half maximal inhibitory concentration (IC50) of TAM-loaded SLNs was generally lower than that of free TAM. Conclusion: This finding indicates that tamoxifen’s cytotoxicity may result from improved drug internalization through encapsulation into the SLN matrix and endocytosis. Therefore, when TAM is incorporated into the SLN carrier system, its antitumoral activity is still preserved, suggesting that SLN is a good carrier for the drug insoluble in water.