Preparation of the Chitosan/Poly-γ-Glutamic Acid/Glabrid in Hybrid Nanoparticles and Study on its Releasing Property

Aim: The aim of this study was to encapsulate glabridin (GB) into nanoparticles, prepared by an ionic-gelation method blended with chitosan (CS) and poly-γ-glutamic acid (γ-PGA) to address the issue of poor stability and low water solubility of glabridin. Methods: The physicochemical properties of nanoparticles were investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and fourier-transform infrared (FT-IR) spectroscopy. Results: FT-IR results indicated that the spontaneous interaction between CS, γ-PGA and GB can form a cross linked network-structure, leading to the spontaneous formation of nanoparticles. Morphology of the complex particles was nano-scale spherical shape. Furthermore, particle size was decreased according to the decrease of γ-PGA contents and CS, accompanying with the increase of mixed solution transmittance. The mγ-PGA : mGB = 1: 1 and mCS: (mγ-PGA + mGB) =1: 1 were considered to be a proper preparation condition of CS/γ-PGA/GB hybrid nanoparticles, which produced the smaller nanoparticles with the satisfactory encapsulation efficiency (EE), loading content (LC) and sustained GB release. With the increase of pH values, the potential, EE, and LC decreased gradually, while the particle size increased. The nanoparticles prepared with higher molecular weight γ-PGA had larger particle size and less loading capacity on GB. Additionally, moderate weight ratio of CS/γ-PGA/GB, low pH, and high molecular weight of γ-PGA were favorable for sustained release. Conclusion: It can be concluded that the physicochemical properties of nanoparticles and GB release behaviors were affected by several factors including the weight ratio of CS/γ-PGA/GB, pHvalues, and γ-PGA molecular weight (MW). Nanoencapsulation using CS, γ-PGA and GB has a potential application for the development of functional cosmetic products with skin-whitening effect.