PROBLEM TO BE SOLVED: To provide a freeze-dried preparation containing high-purity PTH peptide and a production method thereof. Also provided is a method for examining a PTH related substance for confirming the purity of a lyophilized preparation containing a PTH peptide. In the present invention, a PTH related substance produced during the production process of a lyophilized preparation containing a PTH peptide is provided. Existence was confirmed. Furthermore, it discovered that the production generation of the said PTH related substance was prevented and reduced notably by suppressing exposure to the air environment in pharmaceutical manufacturing facilities, such as a PTH peptide containing solution. [Selection] Figure 2【課題】 高純度ＰＴＨペプチド含有凍結乾燥製剤及びその製造方法を提供する。また、ＰＴＨペプチド含有凍結乾燥製剤の純度を確認等するためのＰＴＨ類縁物質の検査方法を提供する【解決手段】 本発明において、ＰＴＨペプチド含有凍結乾燥製剤の製造工程中に生成するＰＴＨ類縁物質の存在が確認された。更に、当該ＰＴＨ類縁物質の生成が、ＰＴＨペプチド含有溶液等の医薬品製造施設内空気環境への暴露を抑制することにより顕著に防止・低減されることを見出した。【選択図】 図２
