| abstract |
Provided is a core-shell structure that can achieve both improvement in transdermal absorption of an active ingredient and reduction in skin irritation at a high level. A core-shell structure 10 includes: a core portion 11 containing an active ingredient, the core portion being solid; and a shell portion 12 containing both a first surfactant having a melting point of less than 35° C. and a second surfactant having a melting point of 35° C. or more, the first surfactant and the second surfactant each having an HLB value of 4 to 14, the first surfactant and the second surfactant each containing at least one selected from the group consisting of sorbitan fatty acid esters, glycerin fatty acid esters, propylene glycol fatty acid esters, and fatty acid alkanolamides. |