新環状グアニジン誘導体血糖降下薬DG-5128の熱的性質

抄録

Characteristics of the phase transition exhibited by a hypoglycemic agent DG-5128 (a cyclic guanidine derivative) were examined by differential thermal analysis (DTA) and thermogravimetry (TG). Consequently, the phase transition and its physicochemical mechanism were elucidated as follows. (1) The phase transition of DG-5128 was attributed to the dissolution process of DG-5128 anhydride into free water which was generated from the water of crystallization contained in itself by thermal conversion. (2) The dehydration reaction was a three-dimensional diffusion process following Jander's equation, with an activation energy of 66.3 kcal/mol. In addition, the meaning of crystal or amorphous of DG-5128 anhydride produced from DG-5128 under dehydration conditions, was discussed in relation to the mechanism of the dehydration process.