Nanostructured lipid carrier for bioactive rice bran gamma-oryzanol

Abstract

The current work presents the development of a nanostructured lipid carrier (NLC) as a colloidal encapsulation and controlled release system for bioactive γ-oryzanol (GO) from rice bran oil. GO-loaded NLC (GO-NLC) were prepared using rice bran oil GO via a hot homogenisation method with sunflower oil (liquid lipid) and stearic acid (solid lipid) as the encapsulating lipid matrix, and rice bran phospholipids and Tween 80 as stabilisers. Fabricated GO-NLC had a 95% encapsulation efficiency with a spherical ‘yolk–shell’ morphology and a 143 nm mean particle diameter. A 60-day storage stability study showed that GO-NLC had high GO retention (>90%) at ambient temperature in light and dark conditions. In vitro release studies demonstrated that GO can be released from GO-NLC via different modes: slow controlled release into simulated intestinal fluid, following the Korsmeyer-Peppas model, and rapidly into a surfactant solution (Tween 80), following first-order release kinetics. Lastly, in vitro studies showed encapsulation of GO in NLCs afforded an 18-fold increase in free radical-scavenging activity, a two-fold increase in hyaluronidase-inhibitory, and a 200-fold improvement in anti-inflammatory activity. These suggest that GO-NLC is a suitable GO delivery system, which can either perform as an oral extended-release formulation or a rapid-release, surfactant triggered system, with improved health-promoting bioactivities.