Stability and thermophysical properties of azithromycin dihydrate

The aim of this paper was to describe the temperature effect on the stability and the thermophysical properties of azithromycin (AZ). First, the density, the heat capacity and the solubility of original (commercial) AZ were determined. Second, the original samples were heated at 50 °C and 80 °C and their PLM, DSC, TGA and XRD data were compared to those of the original AZ. According to our results, the original AZ was a dihydrate which converted to anhydrate when heated up to 80 °C. The dehydration induced a change of crystal habit while the crystalline lattice remained unchanged.