Folate-targeted etoposide-encapsulated lipid nanospheres

Abstract

Lipid nanospheres (LN) are simple colloidal drug delivery systems, which are proven to be useful for the systemic delivery of lipophilic anticancer drugs. Our previous work shows that the encapsulation of etoposide in LN improved the anticancer activity and a further inclusion of polyethylene glycol-distearoylphosphatidylethanolamine (DSPE-PEG) increased the circulation time and stability of LN. The present study is focused on the targeting ability of LN using Folate-PEG-DSPE. Folate-targeted (Fol-LNE) and non-targeted (SLNE) etoposide-encapsulated lipid nanospheres were prepared with the help of soybean oil, egg phosphatidylcholine, and PEG-DSPE with and without Folate-PEG-DSPE. The anticancer activity of these formulations was assessed in KB cell line. Cell uptake studies were carried out in KB cell lines using fluorescent-labeled targeted (Fol-LN) and non-targeted (SLN) lipid nanospheres without etoposide. Confocal microscopy and flow cytometry results found that, Fol-LN was selectively taken up by the KB cells and the addition of 1 mM folic acid completely blocked this uptake. Cytotoxicity results support the above finding, the IC50 values of etoposide solution, Fol-LNE, and Fol-LNE-comp (competition with 1 mM folic acid) were 33, 5, and 19 μM, respectively. Tissue distribution of Fol-LNE was compared with that of SLNE and etoposide commercial formulation (ETP) in normal mice. The studies show that in the kidney etoposide concentration was higher following Fol-LNE administration than SLNE and ETP.