Yu L, Mishra D S, Rigsbee D R
Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, Indiana 46285, USA.
J Pharm Sci. 1998 Jun;87(6):774-7. doi: 10.1021/js970224o.
Due to its strong tendency to crystallize, the glass properties of mannitol cannot be measured directly. However, because mannitol can exist in a fully or partially amorphous state in drug formulations, it is important to determine the glass properties of mannitol. We obtained the glass properties of mannitol by introducing a small amount of sorbitol, an isomer of mannitol, to delay the onset of crystallization. Extrapolation to zero sorbitol concentration yielded the following properties for the mannitol glass: Tg onset = 10.7(o)C, Tg midpoint= 12.6( o)C, Tg end = 18.4 degreesC and DeltaCp = 1.27 J/g/K. In addition, we estimated the following parameters of the mannitol glass from the width of glass transition using the results of Moynihan (J. Am. Ceram. Soc. 1993, 76, 1081) and Angell (J. Phys. Chem. 1994, 98, 13780): DeltaH (at Tg onset) = 103 kcal/mol, D = 11, and T0 = 222 K. The value of T0 is consistent with the Kauzmann temperature TK (236 K) obtained calorimetrically. The properties of the mannitol glass may be useful for predicting the behavior of amorphous mixtures containing mannitol.
由于甘露醇具有很强的结晶倾向，其玻璃态性质无法直接测量。然而，由于甘露醇在药物制剂中可以以完全或部分无定形状态存在，因此确定甘露醇的玻璃态性质很重要。我们通过引入少量甘露醇的异构体山梨醇来延迟结晶的开始，从而获得了甘露醇的玻璃态性质。外推至山梨醇浓度为零时，得到了甘露醇玻璃态的以下性质：玻璃化转变起始温度（Tg onset）=10.7℃，玻璃化转变中点温度（Tg midpoint）=12.6℃，玻璃化转变终止温度（Tg end）=18.4℃，以及热容变化（ΔCp）=1.27 J/g/K。此外，我们根据莫伊尼汉（《美国陶瓷学会杂志》，1993年，76卷，1081页）和安吉尔（《物理化学杂志》，1994年，98卷，13780页）的结果，利用玻璃化转变宽度估算了甘露醇玻璃态的以下参数：玻璃化转变起始温度下的焓变（ΔH（at Tg onset））=103 kcal/mol，D = 11，以及T0 = 222 K。T0的值与通过量热法获得的考兹曼温度TK（236 K）一致。甘露醇玻璃态的性质可能有助于预测含甘露醇的无定形混合物的行为。
