PROBLEM TO BE SOLVED: To provide an inorganic nuclear particle with improved elutability of an agent.SOLUTION: A complex nuclear particle for forming a film comprising an agent on the surface is characterized in that (1) a ground layer containing a water-soluble inorganic salt as an outermost layer is formed on the surface of the particle containing a pharmaceutically acceptable inorganic material, (2) the ground layer is used to form the film so as to contact with the surface, and (3) the content of the ground layer is more than 3 pts.wt. relative to 100 pts.wt. of the particle comprising a pharmaceutically acceptable inorganic material.
