Stabilization potential of acidified corn starch in vitamin E enriched coconut oil emulsions for extemporaneous topical formulations

Abstract

In this study, the stabilizing potential of corn starch acidified with hydrochloric acid (ACS) in comparison with Tween 80 was evaluated in vitamin E enriched coconut emulsions for use in extemporaneous topical formulations. Emulsions containing vitamin E and coconut oil (2:3) as lipid phase and different concentrations (1.5 – 5.0 %w/w) of ACS (or Tween80®) in phosphate buffer as aqueous phase were formulated at 27± 2 0C. , Droplet sizes and shapes, pH and rheological properties were evaluated. Acidified CS was analysed using FTIR spectroscopy Emulsions stabilized with ACS and Tween80 were cream and yellow coloured respectively, with the intensity of the colour increasing as the concentration increased. The emulsions were non-offensive and easily re-dispersed on shaking. Emulsions containing ACS had larger droplet sizes (18.34± 1.14 33.27± 1.32 μm) and were more spherically shaped with higher pH values(6.80-6.95), showing dilatant and pseudoplastic flows at low and high shear rates respectively. The viscosity of emulsions stabilized at 2.5 %w/w and 5.0 %w/w remained unchanged after seven days. Acidified corn starch has stabilizing potentials comparable with Tween 80® when incorporated in vitamin E enriched coconut oil emulsions for extemporaneous topical formulations.