The present invention provides a method for producing a microcapsule formulation comprising:step A of adding a basic amino acid to an aqueous solvent containing a heavy metal salt of a peptidic physiologically active substance to obtain an amino acid-containing S/W suspensionstep B of adding a basic amino acid to an organic solvent containing a biodegradable polymer to obtain an amino acid-containing polymer solutionstep C of dispersing the amino acid-containing S/W suspension in the amino acid-containing polymer solution, which is an oil phase, to obtain an S/W/O emulsionstep D of dispersing the S/W/O emulsion in a water phase to obtain an S/W/O/W emulsion andstep E of removing the organic solvent from the S/W/O/W emulsion.The method is capable to avoid direct contact of a peptidic physiologically active substance with an organic solvent layer, and to achieve a high encapsulation efficiency of the peptidic physiologically active substance.
