Saleki-Gerhardt A, Stowell J G, Byrn S R, Zografi G
School of Pharmacy, University of Wisconsin, Madison 53706, USA.
J Pharm Sci. 1995 Mar;84(3):318-23. doi: 10.1002/jps.2600840311.
The trisaccharide raffinose was prepared in its crystal pentahydrate, anhydrous methanolate, and amorphous forms and evaluated with regard to dehydration and hydration properties at various temperatures and relative humidities. The pentahydrate, when stored at relative humidities (RHs) of < 60% but > 10%, showed no loss of water after 3 months of storage at 30 degrees C. When stored below 10% RH, only one water molecule could be removed over a period of 3 months, whereas within 24 h at 30 degrees C in a vacuum oven, two water molecules were removed with no change in crystal structure. Increasing the temperature to 60 degrees C progressively removed the remaining three molecules, causing the crystal, however, to collapse into an amorphous form identical to one prepared by lyophilization. Rehydration at 30 degrees C, which was sufficient to reduce the glass transition temperature to < 30 degrees C, rapidly restored the pentahydrate crystal structure. Rehydration of the methanolate also restored the pentahydrate structure. The significant amount of water accommodated by raffinose in both the crystalline and amorphous forms would appear to make it a potentially useful water scavenger in certain types of dosage forms.
以五水合物晶体、无水甲醇化物和无定形形式制备了三糖棉子糖，并在不同温度和相对湿度下对其脱水和水合特性进行了评估。五水合物在相对湿度（RH）<60%但>10%的条件下储存时，在30℃储存3个月后未出现水分损失。当在低于10%RH的条件下储存时，在3个月的时间内只能去除一个水分子，而在30℃的真空烘箱中24小时内，两个水分子被去除，晶体结构无变化。将温度升至60℃可逐渐去除剩余的三个分子，但会导致晶体坍塌成与冻干制备的无定形形式相同的形态。在30℃进行水合作用，足以将玻璃化转变温度降低至<30℃，能迅速恢复五水合物晶体结构。甲醇化物的水合作用也能恢复五水合物结构。棉子糖在结晶和无定形形式中容纳的大量水分似乎使其在某些类型的剂型中成为一种潜在有用的水分清除剂。
