Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Division of Pharmaceutics, Freeze Drying Focus Group, 91058 Erlangen, Germany.
GILYOS GmbH, Friedrich-Bergius-Ring 15, 97076 Wuerzburg, Germany.
J Pharm Sci. 2018 Aug;107(8):2179-2191. doi: 10.1016/j.xphs.2018.04.016. Epub 2018 Apr 24.
The goal of the present study was to assess the applicability of dynamic vapor sorption analysis of freeze-dried products. Water vapor sorption profiles of intact and ground cakes were recorded to determine the relevance of powder handling. Grinding prior to measurements appeared to be related with a more rapid uptake of water vapor and crystallization. Crystallization may be prevented when analyzing intact cakes. More hygroscopic materials appeared to require a longer time to achieve a constant mass. The specific surface area of different freeze-dried products was calculated from the sorption isotherms using water, organic solvents, and krypton. The specific surface areas calculated for mannitol with water and ethanol was in good agreement with krypton data. False high values were obtained from water vapor sorption of the investigated amorphous materials. The results were slightly improved by the application of vacuum. For trehalose and sucrose, no sorption and thus faulty results were detected with the studied organic solvents. The degree of crystallinity of mannitol within a binary formulation could not be determined by dynamic vapor sorption. Differences in sorption and crystallization tendencies of mannitol and sucrose that were freeze-dried separately and in a binary mixture were considered as the root cause.
本研究的目的是评估用于冻干产品的动态蒸汽吸附分析的适用性。记录完整和粉碎的蛋糕的水蒸气吸附曲线，以确定粉末处理的相关性。在测量之前进行粉碎似乎与更快地吸收水蒸气和结晶有关。在分析完整的蛋糕时可能会阻止结晶。更吸湿的材料似乎需要更长的时间才能达到恒定的质量。使用水、有机溶剂和氪从吸附等温线上计算出不同冻干产品的比表面积。用水和乙醇计算的甘露醇的比表面积与氪数据非常吻合。从研究的无定形材料的水蒸气吸附中获得了错误的高值。通过应用真空，结果略有改善。对于海藻糖和蔗糖，在所研究的有机溶剂中未检测到吸附，因此检测结果有误。通过动态蒸汽吸附无法确定甘露醇在二元配方中的结晶度。甘露醇和蔗糖在单独冷冻干燥和在二元混合物中的吸附和结晶趋势的差异被认为是根本原因。
