Pharmaceutical Emulsions and Creams

O/W-creams with crystalline gel structures in general are four phase systems consisting of a hydrophilic gel phase and a lipophilic gel phase. The first one is able depending on the polarity of surfactants to incorporate a certain amount of water in between the lamellae and to further fix the bulk water (third phase) as coherent (outer) phase. The lipophilic gel phase stabilizes the dispersed (inner) phase (fourth phase). This concept showed its validity for gel structures in O/W-creams built up by ionic and non-ionic surfactants.