Cellular uptake and cytotoxicity of solid lipid nanospheres (SLN) incorporating doxorubicin or paclitaxel

Solid Lipid Nanospheres (SLN) are colloidal therapeutic systems proposed fo r several administration routes and obtained by dispersing warm microemulsi ons in cold water. SLN as carriers of doxorubicin and paclitaxel have been previously studied. In this study, the cellular uptake of SLN and the cytot oxicity of doxorubicin and paclitaxel incorporated into SLN were investigat ed on two cell-lines, human promyelocytic leukemia (HL60) and human breast carcinoma (MCF-7). Cellular uptake of SLN was determined by incorporating 6 -coumarin as fluorescent marker. The cellular uptake of fluorescent SLN was clearly evidenced by fluorescence microscopy. The cytotoxicity of doxorubi cin incorporated in SLN was higher compared to the conventional doxorubicin solution, even at the lower concentrations. Paclitaxel in SLN was about 10 0-fold more effective than free paclitaxel on MCF-7 cells, while on HL60 ce lls a lower sensitivity was achieved with paclitaxel in SLN. Unloaded SLN h ad no cytotoxic effect on HL60 and MCF-7 cells. (C) 2000 Elsevier Science B .V. All rights reserved.