Amphotericin B loaded solid lipid nanoparticles (SLNs) and nanostructured lipid carrier (NLCs): physicochemical and solid-solution state characterizations

Abstract

Amphotericin B (AmB) is one of the most effective systemic antifungal agents, but its use is circumscribed by the dose-limiting toxicity of the conventional micellar dispersion formulation, Fungizone^®. Significantly lesser toxicity is obtained when AmB incorporated into the aqueous dispersion of lipid nanoparticles. The aim of this study was to develop and characterize AmB loaded solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). NLC differed from SLN by the presence of liquid lipid, glyceryl tri(caprylate/caprate) in the lipid matrix. Various surfactants i.e. tween 20, cremophor RH40, poloxamer 407 (P407) and Myrj 52 were used to stabilize SLN and NLC. The effect of phospholipid incorporated in those lipid dispersions was also determined. Among surfactants tested, only P407 could stabilize AmB lipid dispersions. There was no chemical reaction occurred between AmB and other components that confirmed by Fourier transform infrared spectroscopy (FT-IR) spectra. The differential scanning calorimetry (DSC), hot-stage microscopy (HSM), powder X-ray diffractometry (PXRD) data showed that AmB was molecularly dispersed or in amorphous form in the lipid matrix. The proton nuclear magnetic resonance (¹H-NMR) results showed that in the presence of phospholipid oil clusters within the lipid matrix are formed. These results indicate that SLN and NLC stabilized by P407 and/or phospholipid as the colloidal carrier for AmB were successfully developed.

Keywords: Solid lipid nanoparticles; high pressure homogenization; characterization; nanostructured lipid carriers; amphotericin B.