Self-reporter shikonin-Act-loaded solid lipid nanoparticle: formulation, physicochemical characterization and geno/cytotoxicity evaluation.

Shikonin and some of its derivative have approved apoptotic potential in different human cancer cell lines, and moreover have a dominant fluorescent emission at ∼600nm. Here, to enhance shikonin-Act anti-proliferation properties, it was successfully incorporated in Solid Lipid Nanoparticles (SLNs) by the hot homogenization and entrapment efficiency (EE) of drug in SLNs was determined by ultrafiltration method. Scanning electron microscopy (SEM), laser diffractometry and zeta-sizer indicated that shikonin-Act-SLN were spherical and regular particles in the range of 70-120nm with polydispersity index (PI) of less than 0.10. The physical stability of shikonin-Act-loaded SLN in aqueous dispersion was evaluated in terms of size, PI, EE and drug leakage and the results showed that SLNs were stable upon storing three month. Long term in vitro release of the shikonin-Act was also approved. Cellular uptake of the shikonin-Act-SLN was examined by the in vitro fluorescent microscopy and facs flow cytometry analyses. In vivo rat imaging approved the penetrating capability of shikonin-Act-SLN emission through living tissues. In vitro anti-proliferation and genotoxicity evaluation by MTT and comet assay confirmed that shikonin-Act-SLN showed higher cytotoxic/antitumor potential than intact shikonin in terms of IC50 and DNA damage. This work provide sufficient information about improving of the therapeutic efficacy of the shikonin-Act, and also using of the shikonin-Act-SLN in bio-distribution studies during drug delivery investigation by incorporating in lipidic and colloidal drug delivery particles such as SLNs.