Abstract
O1+O2+…/W type emulsion, which we discuss in this article means the cream which the oil droplets with different properties such as O1 (which has a good sense for skin) and O2 (which has high mutual solubility with an active component) were dispersed.
The continuous phase of O1+O2+…/W type emulsion comprises surfactant (D) phase formed by surfactant, co-surfactant (ex. fatty alcohol) and water, but it is difficult to stabilize O1+O2+…/W type because of a movement of each oil through the D phase.
The miscibility between D phase and oil was investigated on the basis of D phase properties, i.e. total surfactant conc., HLB, the addition of water-soluble polymer. As a result, it was found that making the surfactant conc. as low as possible and the addition of water-soluble polymer (sodium hyaluronate, CP (934)-K) with high bound water contents were impotant factors in order to reduce the miscibility and then stabilize O1+O2+…/W type. It seems that the addition of water-soluble polymer changes hydration state of D phase, that is, makes HLB of D phase shift toward hydrophilic property.
In addition, it was demonstrated that the sensual evaluation of O1+O2+…/W type emulsion was different from that of mix-oil emulsion which O1 and O2 mixed each other.
Thus, it was suggested that emulsions combined both various sensual state and stable encapsulation of an active component were expected for O1+O2+…/W type.
