This study was aimed at preparing and characterising kojic acid nanostructured lipid carriers (KA-NLCs) for delivery to skin. KA-NLCs were prepared using high-speed homogenization followed by ultra-probe sonication method. KA-NLCs were optimized by glyceryl mono-stearate (GMS) and cholesterol (Chol) as solid lipid excipients, oleic acid (OA) as liquid lipid excipient, span 60 (SP 60) and Tween 20 (Tw 20) as co-emulsifiers. For optimized formulation (KA-NLC3), values of particle size, encapsulation efficiency, drug loading, polydispersity index (PDI) and zeta potential (ZP) were found to be 172.9 ± 7.1 nm, 76.4 ± 0.1%, 17.6 ± 1.3%, 0.3 ± 0.1 and -39.1 ± 2.7 mV, respectively. KA-NLC3 was stable at 4 °C and 25 for 3 months. TEM image confirmed these results. ATR-FTIR, DSC and PXRD results indicated suitable entrapment of KA in NLCs without any chemical interaction. The release profile of KA-NLC3 followed a sustained pattern. KA-NLC3 has potent tyrosinase inhibitory activity in comparison with pure KA. Nanoparticles showed a higher antioxidant activity than pure KA. The results of the ex vivo and in vitro percutaneous absorption showed that KA-NLC3 improved percutaneous delivery of KA. Concentrations below 250 μg/mL were determined as suitable concentrations for KA-NLC3. It seems to be biocompatible formulation for the cosmetics aims.
Keywords: Melanin; hydrophilic depigmenting agents; kojic acid; nanostructured lipid carrier; skin permeation.