| abstract |
Disclosed is a film coating agent for a solid preparation, which has excellent water vapor barrier properties and is thus capable of stably maintaining the quality of medicinal ingredients even in cases when the solid preparation is stored unpacked for a long term. Specifically disclosed is a film coating agent for a solid preparation, which contains a water-soluble cellulose derivative, swellable clay, a cationic surfactant and a fatty acid. The mass ratio of the swellable clay to the water-soluble cellulose derivative is from 2:8 to 8.2, and the cationic surfactant is contained in an amount of 0.5-3.0 equivalents (inclusive) per cation exchange equivalent of the swellable clay. |