@Article{, title={Formulation ancl Evaluation of a Topical Antioxidant Preparation دراسة وتقييم الصيغة التركيبية لمستحضر موضعي مضاد للاكسدة}, author={Hassan Ahmed Hassan حسن احمد حسن and Emad Muthana Yousif عماد مثنى يوسف and Ali Ahmed Yas علي احمد ياس}, journal={Tikrit Journal of Pharmaceutical Sciences مجلة تكريت للعلوم الصيدلانية}, volume={3}, number={2}, pages={152-169}, year={2007}, abstract={The aim of this work was to prepare the stable vitamin C rvater/oilirvater (w/o/w)
multiple emulsions, to investigate the usage of poloxamine 908, to observe the influence of
surfactant percentage on the properties of multiple emulsions. Multiple emulsions were prepared by
liquid paraffin, cetyl dimethicone copolyol and poloxamine 908 by a two - step emulsification
procedure. Vitamin C r,vas used as an antioxidant and r,vater - soluble model. The viscosity,
conductivity and globule size of multiple emulsions rvere follor,ved over time. The formulations
containing 1o/o cetyl dimethicone copolyol and I or Zoh poloxamine 908 lvere the most stable
systems. The globule size of multiple emulsions ranged from 20 to 37 pm and did not change
during time. The yield of multiple en-rulsions rvas betrveen 99.6Yo and 98.7o/o. The conductivity
increased and the viscosity of systems decreased during time. Increase in poloxamine 908
influenced the viscosity of the system, rvith the viscosity decreasing as the hydrophitic surfactant
concentrations were increased. Vitamin C rclease lronr the multiple emulsions u'as slow'; the release
rvas aft'ccted by both surlactant concentratior.rs. Poloxanrirre 908 could be used as a hydrophilic
surfactant for formulation of rv/o/rv multiple emulsions. The concentration of poloxanrine 908 was a
very important parameter in preparing stable multiple enrulsions. It 'uvas concluded that vitamin C
might be transported out by molecular diffusion and through a reverse micellar mechanism
controlled by the viscosity of the system

} }