Alpha-lipoic acid-loaded nanostructured lipid carrier: sustained release and biocompatibility to HaCaT cells<i>in vitro</i>

ALA-loaded nanostructured lipid carrier (ALA-NLC) was designed to improve physicochemical stability and water solubility, and promote sustained release of ALA as well as determine the biocompatibility of ALA-NLC. The ALA-NLC manufactured using hot high-pressure homogenization technique was investigated in terms of size, zeta potential, FTIR analysis and release behavior. In vitro cytotoxicity and biocompatibility were determined by incubating with HaCaT cells using the MTT assay, HE staining and Hoechst 33342 staining. Cell behavior and cellular division of HaCaT cells untreated and treated by ALA-NLC were investigated in real-time images gathered using time-lapse imaging system. The release investigation illustrated that only 6.9% of ALA released in 30 min from ALA-NLC formation, whereas it was 30.3% in free ALA system. ALA-NLC possessed a satisfactory release behavior of sustained release up to 72 h. It showed that ALA-NLC did not exert hazardous effect on HaCaT cells up to 81.9 mg/L without morphological alterations, revealing a satisfactory biocompatibility. Evidence was provided from time-lapse imaging system that cell behavior and cellular division of ALA-NLC treated HaCaT cells were in accordance with the control. These results of this investigation demonstrated that NLC encapsulated ALA formation (ALA-NLC) can improve stability, solubility and release of ALA; ALA-NLC was biocompatible to HaCaT cells.