市售硬脂酸镁吸湿特性的研究。
An examination of the moisture sorption characteristics of commercial magnesium stearate.
作者信息
Swaminathan V, Kildsig D O
机构信息
Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47906, USA.
出版信息
AAPS PharmSciTech. 2001 Dec 3;2(4):73. doi: 10.1007/BF02830568.
The objective of this study was to characterize the moisture sorption of magnesium stearate and the morphological changes, if any, resulting from moisture sorption. Six samples of commercial magnesium stearate USP were examined. Moisture sorption isotherms were obtained at 25 degrees C and 5% to 98% relative humidity (RH) using a moisture balance. Changes in crystal form resulting from moisture sorption were determined by x-ray diffraction. There were differences in the shape of the isotherm, reversibility of moisture uptake, and shape of the hysteresis loop in the isotherms of crystalline and amorphous magnesium stearates. The isotherm of crystalline magnesium stearate was almost parallel to the pressure axis until an RH of ~80% was reached, when there was desorption of practically all of the adsorbed water. The isotherm of the amorphous sample was characterized by continuous uptake of water over the entire range of RH. Exposure of amorphous magnesium stearate to RH greater than 70% resulted in the formation of the trihydrate. The trihydrate was converted into the anhydrous form when heated to a temperature of 100 degrees C to 105 degrees C. The trihydrate could be generated by exposing the anhydrate to RH higher than 70%.
本研究的目的是表征硬脂酸镁的吸湿情况以及吸湿导致的形态变化（若有）。对六个美国药典级商业硬脂酸镁样品进行了检测。使用水分平衡仪在25℃和5%至98%相对湿度（RH）下获得吸湿等温线。通过X射线衍射确定吸湿导致的晶体形态变化。结晶态和无定形硬脂酸镁的等温线形状、吸湿的可逆性以及等温线中滞后环的形状存在差异。结晶态硬脂酸镁的等温线在达到约80%RH之前几乎与压力轴平行，此时几乎所有吸附的水都会解吸。无定形样品的等温线特征是在整个RH范围内持续吸水。将无定形硬脂酸镁暴露于大于70%的RH会导致三水合物的形成。将三水合物加热到100℃至105℃时会转化为无水形式。通过将无水物暴露于高于70%的RH可生成三水合物。
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