Otsuka M, Onoe M, Matsuda Y
Department of Pharmaceutical Technology, Kobe Women's College of Pharmacy, Japan.
Pharm Res. 1993 Apr;10(4):577-82. doi: 10.1023/a:1018906320932.
The physicochemical stability of six phenobarbital modifications [forms A, B, C (monohydrate), D (dioxane solvate), E (hemihydrate), and F] at various levels of humidity and temperature were measured using X-ray diffractometry and differential scanning calorimetry. Form D was identified as a new crystalline form (dioxane solvate). Polymorphic transformations of the modifications were investigated by the Kissinger method under nonisothermal conditions. Change of polymorphic content of phenobarbital modifications under various humidity levels at 45 degrees C was evaluated by X-ray powder diffraction. The polymorphic stability under isothermal conditions was estimated kinetically, based upon the Jander equation. Forms A, B, and F were stable at 0 and 75% RH and 45 degrees C for 3 months. On the contrary, forms C, D, and E transformed during storage. The transformation rates of form D were larger than that of forms C and E.
使用X射线衍射法和差示扫描量热法测定了六种苯巴比妥变体[晶型A、B、C（一水合物）、D（二氧六环溶剂化物）、E（半水合物）和F]在不同湿度和温度水平下的物理化学稳定性。晶型D被鉴定为一种新的晶型（二氧六环溶剂化物）。采用基辛格方法在非等温条件下研究了这些变体的多晶型转变。通过X射线粉末衍射评估了45℃下不同湿度水平下苯巴比妥变体多晶型含量的变化。基于扬德方程，对等温条件下的多晶型稳定性进行了动力学估算。晶型A、B和F在0%和75%相对湿度以及45℃下3个月内保持稳定。相反，晶型C、D和E在储存过程中发生了转变。晶型D的转变速率大于晶型C和E的转变速率。
