Novel calcitonin derivative and salt thereof

摘要

There is disclosed a calcitonin derivative and its salt, comprising an amino acid residue at the 1-position of calcitonin which is a cyclic amino acid residue represented by the formula: <IMAGE> (I) wherein X represents a sulfur atom or a methylene group; and n represents an integer of 0 or 1. and an amino acid residue at the 7-position which is a cysteine residue which may be substituted with an appropriate protective group.