α-Tocopherol encapsulation and in vitro release from wheat gliadin nanoparticles

Alpha-tocopherol, or vitamin E (VE), is widely used as a strong antioxidant in many medical and cosmetic applications, but is rapidly degraded, because of its light, heat and oxygen sensitivity. Thus, all of its formulation has to avoid contact with light, heat or air. Drug loaded carriers are an attractive opportunity, especially if they are made for bioacceptable macromolecules such as vegetal proteins. For instance, gliadins, extracted from wheat gluten, generate nanoparticles by a desolvatation method and may interact with epidermal keratin for therapeutic or cosmetic formulations. Their lipophilic drug loading capacities have been investigated. The VE loaded gliadin nanoparticles have been characterized by their size, by their zeta potential, by their VE payload, and by their entrapment efficiency. When VE loaded, the gliadin particle size is approximately 900 nm and their charge is close to zero. They are suitable VE drug carriers with an optimum encapsulation rate approximately 100 VE microg/gliadin mg with an efficiency of more than 77%. The release behaviour of VE loaded nanoparticles may be interpreted as a 'burst effect', followed by a diffusion process through an homogeneous sphere.