Cholesteryl butyrate in solid lipid nanospheres as an alternative approachfor butyric acid delivery

Background: Cholesteryl-butyrate chosen as lipid matrix of solid lipid nano spheres (SLNs) could be a suitable pro-drug to delivery butyric acid and ov ercome one of the most limiting disadvantages of the compound: the short ha lf-life due to a rapid metabolism. Methods: We evaluated the antiproliferat ive effect, with respect to that of sodium butyrate, of four SLNs (SLN1, SL N2, SLN3 and SLN4) characterized by a different concentration of cholestery l-butyrate (range, 1.7-30 mM) on NIH-H460, a non-small cell lung carcinoma cell line. Results: After 6 days of treatment, all SLN preparations induced a dose-dependent inhibition of NHI-H460 cel growth: the most effective SLN preparation (SLN1) was able to induce a complete growth inhibition already at 0.25 mM, a concentration at which sodium butyrate induced only a a 55% inhibition. Fluoresce microscopy showed that 6-coumarin-tagged SLNs were al most completely internalized by cel after 5 min of treatment. Conclusions: The present results indicate that owing to their peculiar characteristics, SLNs could be an interesting alternative approach for butyric acid delivery into tumor cells.