Preparation and characterization of retinyl palmitate niosomes

Abstract

Retinyl palmitate niosomes were prepared by hand-shaking method using Span 40, Span 60 and Span 85, cholesterol and Solulan C-24 as the niosomal membranes. The molar ratio of Span:cholesterol:Solulan C-24 was 45:45:10 with the total lipid/surfactant fo 300 micromoles in 9 ml (33.33mM). The obtained niosomes were spherical and showed multilamellae with their mean diameter 10 microns. The retinyl palmitate loading optimization was studied with the concentration of retinyl palmitate varied from 5,8 and 10 mg. The highest percentage of entrapment of retinyl palmitate was 100% when retinyl palmitate was added at 5 mg in niosome suspensions. The effect of cholestreol on retinyl palmitate entrapment was investigated with the molar ratio of cholesterol varying from 0-80% using 8 mg of retinyl palmitate. The higher the concentration of cholesterol was in niosomes, the lower the amount of retinyl palmitate could be entrapped in Span 40 and Span 60 niosomes. On contrary to Span 85, the entrapment of retinyl palmitate was increased with an increase of cholesterol prepared by Span 85. The permeation of retinyl palmitate niosomes that were prepared by Span 40:cholesterol:Solulan C-24 (45:45:10) through the snake skin (Cobra) showed the highes cumulative retinyl palmitate and its flux.