Identifying and Mapping Surface Amorphous Domains
Identifying and Mapping Surface Amorphous Domains
复制标题
识别和绘制表面非晶域
DOI：
10.1007/s11095-005-6027-4
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发表时间：
2005
影响因子：
3.7
通讯作者：
S. Ebbens
中科院分区：
文献类型：
--
作者：
Stuart Ward;M. Perkins;Jianxin Zhang;C. Roberts;C. Madden;S. Luk;N. Patel;S. Ebbens
PurposeUndesirable amorphous material generation during formulation is implicated in a growing number of pharmaceutical problems. Due to the importance of interfacial properties in many drug delivery systems, it seems that surface amorphous material is particularly significant. Consequently, this study investigates a range of methods capable of detecting and mapping surface amorphous material.MethodsA micron-sized localized surface domain of amorphous sorbitol is generated using a novel localized heating method. The domain is subsequently investigated using atomic force microscopy (AFM) imaging, nanomechanical measurements, and Raman microscopy 3-D profiling.ResultsAFM phase and height images reveal nanoscale-order variations within both crystalline and amorphous sorbitol domains. Nanomechanical measurements are able to quantitatively distinguish the amorphous and crystalline domains through local Young’s modulus measurements. Raman microscopy also distinguishes the amorphous and crystalline sorbitol through variations in peak width. This is shown to allow mapping of the 3-D distribution of the amorphous phase and is hence complementary to the more surface sensitive AFM measurements.ConclusionsAFM and Raman microscopy map the distribution of amorphous material at the surface of a sorbitol crystal with submicron spatial resolution, demonstrating surface analysis methods for characterizing semicrystalline solids generated during pharmaceutical processing.
