It was demonstrated that some level of order exists in glassy poly(ethylene terephthalate) by depolarized light intensity(DLI) technique, but this order is different from that in crystalline PET. The degree of order in glassy PET decrease with increasing temperature between 288-343 K. The active energy of this transition is about 22 56 kJ/mol. The IR analysis indicated that this order relates to gauche structure of the ethyleneglycol fragments. The decrease of order with temperature comes from the increase of distance between the order segments.
目的测定那格列奈的多晶结构和药效,给出晶格参数和动物试验数据。方法X射线粉末衍射法测定物相和晶格参数;腹腔注射葡萄糖致使小鼠形成高血糖血症。小鼠分成对照组、模型组、H晶型治疗组和S晶型治疗组。测定给药20,40和60 m in后小鼠的血糖值。结果那格列奈有3种晶型,B-,H-和S-型结构。H晶型为三斜晶系,晶格参数a=1.769 9(7)nm,b=2.719 1(8)nm,c=1.267 0(6)nm,α=61.75(3)°,β=73.11(6),°γ=66.77(7),°V=4.895 nm3,Z=10。S晶型为正交晶系,晶格参数a=2.317 8(6)nm,b=2.533 2(5)nm,c=0.653 1(2)nm,α=β=γ=90°,V=3.835 nm3,Z=8。小鼠模拟降糖试验表明:与H晶型一样,S晶型也能有效地降低血糖值,特别是用药40 m in后效果更加明显。结论H晶型为三斜晶系,S晶型为正交晶系,用S晶型给药40 m in后效果更加明显。
