MECHANISM OF STABILLIZATION BY CETYL ALCOHOL FOR OIL IN WATER CREAM

Abstract

It is known that oil-in-water creams or ointments used in cosmetic or pharmaceutical products increased in consistency and stability on adding of cetyl alcohol. This paper reports the effects of the polymorphism of the alcohol and the cooling procedures after emulsification on the stability of the cream.
Long chain alcohols are known to exist in three crystal forms, designated as α, β, and γ. The α-form is stable at higher temperatures and transforms into the β- or γ-form at lower temperatures. The creams were stable in the temperature range in which the alcohol crystallized into the α-form, whereas they were broken within a few days in the temperature range in which the alcohol crystallized into the β-or γ-form. The creams that were cooled to 30°C at which the alcohol crystallized into β-or γ-form in a bath containing ice water (fast cooling procedure) were broken within a few days, on the other hand, those cooled to 30°C in air (slow cooling procdure) were stable for a longer period. Liquid clystals found to be formed in this system, which also contributed to stabilizing the creams.