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.

Keywords: Coconut oil emulsions; Vitamin E; Acidified corn starch; Tween80®; Viscosity Emulsion stability, Extemporaneous topical formulations