Taisho Pharmaceutical Co., Ltd.

Tohru Nagahama

Kazuo Hasegawa

Yuji Ito

Toshiaki Nakajima

Tomoaki Yoshino

A W/O/W type composite emulsion, wherein a W/O type emulsion containing water, an oil ingredient and a lipophilic emulsifier each in a proportion expressed in term of mass ratio falling within a range enclosed with bold lines in FIG.is dispersed in an external aqueous phase with a water-soluble macromolecule blended therein has a sufficient stability, and permits preserving a percent inclusion of medical substances included in an internal aqueous phase of the W/O/W type composite emulsion at a high level. Because of the characteristics, it is now possible to blend in a liquid formulation medical substances having an unfavorable taste or unstable medical substances which have to date hardly been included in liquid formulations with low viscosity, so that the W/O/W type composite emulsion can be utilized for liquid formulations including a liquid formulation for internal application, injections, etc.

W/O/W composite emulsion

A microemulsion containing (A) a highly polar and fat-soluble oil drug, a highly polar oil and a lowly polar oil, (B) a polyglycerol mono-fatty acid ester and (C) a water-soluble polyhydric alcohol, wherein the amount of (B) is 0.3 to 3 parts by weight based on one part by weight of (A) and the amount of (C) is 0.1 to 3 parts by weight based on one part by weight of the total amount of (A) and (B). The present invention makes it possible to make a microemulsion containing a highly polar and fat-soluble drug which is highly stable.

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Tokyo, Japan

Tohru Nagahama