ANHYDROUS ALPHA-LACTOSE - A STUDY WITH DSC AND TXRD

The dehydrated lactose forms alpha(H) and alpha(s) were investigated by time- and temperature-resolved X-ray powder diffractometry and differential scanning calorimetry. We found different X-ray structures for these two forms, which is probably related to the different dehydration processes. The rapidly dehydrated form alpha(H) obviously has the same X-ray structure as the starting material alpha-lactose monohydrate, although the crystallinity is reduced. A thermally induced transition of the alpha(H)-form into the alpha(s)-form was observed. This transition should allow one to ''switch'' between the physicochemical properties of the excipient, which may be important for applications in pharmaceutical and food industries.