Comparative and Stability Study of Rice Bran Oil in Nanovesicle: Conventional Niosomes and pH-Sensitive Niosomes

Niosomes are more stable and economical than liposomes. In previous studies, conventional niosomes have shown advantages for transdermal delivery of bioactive compounds from rice bran. The objective of this study was to compare nanovesicle formulations (conventional niosomes and pH-sensitive niosomes) containing oryzanol (OZ) and rice bran oil (RBO). The formulation parameters were varied for the types of model drugs (OZ pure compound and RBO), the content of RBO loading (low, medium, high), and the types of niosomes (conventional niosomes and pH-sensitive niosomes). The physicochemical properties, e.g., vesicle size, size distribution, zeta potential and oryzanol content, were investigated. The stability of nanovesicles during the incubation period from Day 1 to Day 90 was observed. The in vitro skin permeation of the niosome formulation was demonstrated and calculated from the skin permeation flux and the permeability coefficient. The results indicated that the OZ- and RBO-loaded nanovesicle formulation had nanoscale vesicles (under 205 nm) and a narrow size distribution (0.22-0.55). The OZ content in the formulation was up to 300 µg/mL. The RBO-loaded nanovesicle formulations were stable at 4 and 25 °C for 90 days and 40 °C for 30 days. The skin permeation parameters of pH-sensitive niosomes were significantly higher than those of conventional niosomes at a flux of 16.56 ± 3.37 µg/cm2/h and a permeability coefficient of 0.0542 ± 0.011 cm2/h. These results suggest that pH-sensitive niosomes can be promoted and used as drug delivery carriers for rice bran oil. Keywords: Floral biology, Flower, Pollen, Microclimate, Heat unit Rice bran, Oryzanol, Liposome, Oleic acid, Permeability coefficient