A promising and effective platform for delivering hydrophilic depigmenting agents in the treatment of cutaneous hyperpigmentation: kojic acid nanostructured lipid carrier

Abstract

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

Acknowledgments

The authors also would wish to express their sincere and special appreciation to Dr. Mehdi Khalili and their team in Pars Clinic Surgery Center, Sari, Iran, for their valuable and technical cooperation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The financial support from the Vice Chancellor for Research of Mazandaran University of Medical Sciences, Sari, Iran [Grant Number 10322] is greatly acknowledged.