The formulation containing 5% (w/w) self-emulsifying wax (cetearyl alcohol, ceteareth-12, ceteareth-20, glyceryl stearate and cetyl palmitate) and 2% (w/w) isoparafin and polyacrilamide gel was supplemented or not with 2% of L-AA (pH of the final formulation adjusted to 3.5) or 2% of MAP(pH of the final formulation adjusted to 7.0) or 2% of ATIP (pH of the final formulation adjusted to5.5) because these active substances have shown better chemical stability at these pH.