Department of Industrial and Physical Pharmacy, 575 Stadium Mall Drive, Purdue University, West Lafayette, Indiana 47907-2091, USA.
J Pharm Sci. 2010 Sep;99(9):3839-48. doi: 10.1002/jps.22221.
In reality, no crystal is perfect. Crystals bear defects both in the bulk and on the surface. The purpose of this project is to study the correlation between crystal defect density and reactivity of physical transformation. The hypothesis is that larger crystals have the opportunity to pick up more defects during crystal growth than smaller crystals, therefore, have higher reactivity. Flufenamic acid (FFA) was used as a model compound. Phase transformation of crystal Form I (white) to Form III (yellow) of FFA was studied, and observed that larger crystals of FFA Form I transform faster. Furthermore, the etching pits identified on the major crystal faces (1 0 0) using atomic form microscopy (AFM) also showed that larger crystals had higher surface defect density than smaller ones, which correlates with the finding that larger crystals transforms faster than smaller ones.
实际上，没有完美的晶体。晶体在内部和表面都存在缺陷。本项目的目的是研究晶体缺陷密度与物理转化反应性之间的关系。假设是，较大的晶体在晶体生长过程中比较小的晶体有更多的机会获得缺陷，因此具有更高的反应性。氟芬那酸（FFA）被用作模型化合物。研究了 FFA 晶型 I（白色）向晶型 III（黄色）的相变，观察到较大的 FFA 晶型 I 晶体转化更快。此外，使用原子力显微镜（AFM）在主要晶面（100）上识别出的蚀坑也表明，较大的晶体比较小的晶体具有更高的表面缺陷密度，这与较大的晶体比较小的晶体转化更快的发现相符。
