Kawakami Kohsaku, Miyoshi Kyoko, Tamura Naomi, Yamaguchi Tohru, Ida Yasuo
Developmental Research Laboratories, Shionogi & Co., Ltd., Fukushima-ku, Osaka 553-0002, Japan.
J Pharm Sci. 2006 Jun;95(6):1354-63. doi: 10.1002/jps.20458.
Isothermal crystallization of sucrose glass under ambient condition was investigated by powder X-ray diffraction, isothermal microcalorimetry, and water sorption/desorption analysis. Isothermal microcalorimetry measurements showed that the crystallization behavior was affected by the compression force applied to starting amorphous materials. The crystallization rate was analyzed by X-ray diffraction measurements to establish that the rate could well be explained by the Avrami-Erofeev equation. In the water sorption/desorption analysis, the weight change during the crystallization was elucidated by supposing that desorption proceeded from the crystallized part. The sucrose crystallized at relatively low temperature conditions showed completely different melting behavior from that of intact sucrose, although the crystal form was most likely to be identical. This difference could be explained by defects in the lattice structure produced during the crystallization and the desorption process. Correlation was found between the melting temperature and the water content just before the crystallization. Defects in the crystal structure were partially modified by annealing as has been found in relaxation studies of amorphous materials.
通过粉末X射线衍射、等温微量热法和水吸附/解吸分析，研究了蔗糖玻璃在环境条件下的等温结晶过程。等温微量热法测量表明，结晶行为受施加于起始无定形材料的压缩力影响。通过X射线衍射测量分析结晶速率，以确定该速率可以很好地用阿弗拉米-埃罗费耶夫方程来解释。在水吸附/解吸分析中，通过假设解吸从结晶部分开始，阐明了结晶过程中的重量变化。在相对低温条件下结晶的蔗糖表现出与完整蔗糖完全不同的熔化行为，尽管晶体形式很可能是相同的。这种差异可以用结晶和解吸过程中产生的晶格结构缺陷来解释。发现熔化温度与结晶前的含水量之间存在相关性。正如在无定形材料的弛豫研究中所发现的那样，通过退火可以部分修正晶体结构中的缺陷。
