水溶性, 結晶性薬剤の湿潤性に関する研究 (第6報)

抄録

Critical relative humidity (CRH) of the mixture which form double salt, except Na₂SO₄-(NH₄)₂SO₄ mixture, by the pre-equilibrium method, coincided almost with the saturation method when measured under a similar condition to that in the previous report. The X-ray diffraction analysis showed that, at the beginning of moistening, the thermodynamic equilibrium was not maintained between the components in the Na₂SO₄-(NH₄)₂SO₄ mixture.
CRH of the mixture which form solid solution (mixed crystal) of KBr-KCl and NH₄Cl-KCl, by the pre-equilibrium method, coincided with that by the saturation method.
CRH of NaCl-Na₂SO₄ and NaCl-Na₂CO₃ mixtures by both method is not always coincided. The change of solid phase by moistening of 4 kinds of tautomeric double pair salt and CRH by pre-equilibrium method generally correspond with the report by Merz and the calculation equation of CRH in the tautometric double pair salt was examined.