On the physical transformations of processed pharmaceutical solids.
Atomic force microscopy Phase Imaging, an adaptation of Tapping Mode AFM was used to visualise physico-mechanical variations on the surface of crystalline materials after being subjected to mechanically induced lattice damage. Large crystals (100-500 microm) of lactose were nucleated on AFM sample stubs, imaged and subjected to a milling process. The milled samples were then imaged at specific humidity using Phase Imaging. Phase and Amplitude images of the re-crystallised lactose suggested an ordered crystalline state with multiple platelets present across the surface. In comparison, the morphology and surface properties after a 1-min mill time suggested milling had a dramatic effect on the surface characteristics of the re-crystallised lactose. Phase and Topographical imaging during exposure to elevated humidities (70% RH) indicated both morphological and physico-mechanical changes that may be linked to surface amorphous re-crystallisation.
Pharmaceutical Technology Research Group, Department of Pharmacy, University of Bath, UK. prsrp@bath.ac.uk
Robert
R
Price
Paul M
PM
Young
D003460:Crystallization; D007785:Lactose; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D013678:Technology, Pharmaceutical
D007785:Lactose