Galactosylated solid lipid nanoparticles with cucurbitacin B improves the liver targetability

This study intended to prepare liver-targeting solid lipid nanoparticles (SLNs) with a hepatoprotective drug, cucurbitacin B (Cuc B), using a galactosylated lipid, N-hexadecyl lactobionamide (N-HLBA). The galactosyl-lipid N-HLBA was prepared via the lactone form intermediates of lactobionic acid and synthesized by anchoring galactose to hexadecylamine lipid. The Cuc B-loaded galactosylated and conventional SLNs were successfully prepared by a high-pressure homogenization method. The two SLNs showed similar physical and pharmaceutical properties, including: the particle size measured by laser diffraction was 135 nm for galactosylated SLN (GalSLN) and 123 nm for conventional SLNs (CSLN); zeta potentials were -31.6 mV (GalSLN) and -34.3 mV(CSLN); in vitro release behavior of the two SLNs was similar, and both showed the biphasic drug release pattern with burst release at the initial stage and prolonged release afterwards. In contrast, the two SLNs demonstrated a marked difference in in vitro cellular cytotoxicity and in vivo tissue distribution performances. The IC50 values of Cuc B in the two SLNs were by far lower than those of Cuc B solution and further Cuc B-GalSLN had about half the IC50 value of Cuc B-CSLN. These results indicated that the encapsulation of Cuc B in SLNs resulted in the enhancement of cytotoxic activity, and galactosyl ligand could further enhance the cellular accumulation and cytotoxicity of Cuc B. The weighted-average overall drug targeting efficiency (Te) was used to evaluate the liver targetability. Cuc B-GalSLN gave a relatively high (Te)(liver) value of 63.6%, similar to 2.5-times greater than that of Cuc B-CSLN (25.3%) and Cuc B solution (23.8%). In summary, the incorporation of N-HLBA into SLNs significantly enhanced the liver targetability of Cuc B-loaded SLNs and GalSLN had a great potential as a drug delivery carrier for improved liver targetability.