Preparation and characterization of nonionic nano -vesicles prepared from various surfactant types

Abstract

The purposes of this study were to prepare and characterize nonionic nano-vesicles prepared from
various surfactant types (span 20, span 60, span 80, brij 72, glyceryl monostearate and polyethylene glycol-6
stearate). The vesicles were prepared by film hydration followed by high pressure homogenization technique.
Physicochemical properties were investigated by varying molar ratios, total lipids, negative charge inducers,
membrane modifiers, electrolytes, and pH of aqueous phases. Results showed that nonionic vesicles approximately
100 to 200 nm depending on surfactant types could be prepared with narrow size distribution (PDI<0.3).
The vesicle sizes were increased with increasing cholesterol molar ratios and total lipid concentrations. Mixing
nonionic nano-vesicles containing 0, 5, 10 mol% oleic acid as negative charge inducer with osmotic agent,
KCl solution at 60, 40, and 80 mM caused significantly increase in vesicle size and aggregation. Rigid
nano-vesicles were observed when using precirol ATO5 concentrations ≤ 25 mol%. Vesicles were formed
independent of pH of aqueous solutions but aggregations were observed at pH 3 and 5. Differential scanning
calorimetry thermograms revealed that excipients used in the production of nano-vesicles were presented in
amorphous form. These results suggested that a proper selection of excipient can lead to successful encapsulation
of active ingredients for drug and cosmetic applications.