Fatty alcohols or fatty acids as niosomal hybrid carrier: effect on vesicle size, encapsulation efficiency and in vitro dye release

Niosomal hybrid mixtures are prepared with bilayer stabilizer cholesterol from non-ionic surfactants span 20 (HLB value 8.6), span 60 (HLB 4.7) and span 85 (HLB 1.8) in presence of dicetyl phosphate (DCP) where fatty acids or fatty alcohols (C14, C16 and C18) are used as carrier. Hybrid mixtures upon hydration with aqueous phosphate buffer (pH 7.4) spontaneously produce vesicular phase which can encapsulate 5(6)-carboxyfluorescein (CF). Effect of fatty alcohols and fatty acids on the vesicle size has been studied by dynamic light scattering (DLS), freeze-fracture scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Release rates of CF from vesicular suspensions are found to be dependent on carriers as well as surfactants used. Fatty acid coated hybrids form large multilamellar vesicles (LMV) (size range 10-15 microm) where as fatty alcohol coated hybrid systems form small multilamellar vesicles (SMV) with an average diameter of 400 nm, in all cases vesicles are polydisperse (PI approximately 0.9) in nature.