Abstract
Water vapor permeability of hard gelatin capsule films was studied with use of gelatin films prepared in the same method of manufacture of hard capsules. Based on the change in weight of capsule films in the water vapor permeability test, it was suggested that water vapor passes not only through capsule film but through the capsule film-silica gel barrier. The water vapor permeability coefficient rose in parallel with the increase in relative humidity (RH), especially around RH 70%. That may be caused by the change in structure or physical properties of the capsule films due to swelling. The contact of capsule films and silica gel did not significantly affect the permeability coefficient.
