SIMILAR QUALITATIVE AND QUANTITATIVE O W/O AND W/O EMULSIONS - IMPROVEMENT OF COSMETIC PROPERTIES/

The aim of this study was to compare o/w/o multiple emulsions with w/o simple emulsions in terms of occlusivity and remanence. Firstly, four teen o/w/w multiple emulsions were prepared with w/o emulsion componen ts. Several parameters were optimized i.e. primary emulsion/multiple e mulsion ratio, concentration of the emulsifiers, mixing speed. The yie ld and stability of the preparation were measured by a tracer release method using phthalic acid diethyl ester. This tracer, introduced in t he inner oily phase, was chosen according to general requirements : a high oil/water diffusion coefficient, good stability under various pH and temperature,and easy detection. From entrapment yield and droplet breakdown curves calculated from the tracer UV spectrophotometric data , one emulsion was selected for comparison with the w/o emulsion. Skin oil level measurements with a sebumeter provided efficient data to ev aluate the remanence. Occlusivity was measured by the gravimetric meth od of water loss with gelatin cells. The remanence improved significan tly, since the occlusivity properties were retained. As the total perc entage of oil was the same within the two emulsions, the increase of r emanence is mainly due to the galenic form.