THE STUDY OF THE POLYMORPHISM OR ERYTHROMYCIN BASE

The polymorphism of erythromycin base samples obtained in various solv ents has been studied by IR spectroscopy, S-rag diffraction and therma l analysis and was explained by the competition between various types of inter- and intramolecular hydrogen bonds. Among the samples examine d, three were evidenced to be polymorphic variants of crystalline dihy drate, one a crystalline solvate, one an amorphous solid and other a c rystalline anhydrate. The different crystalline dihydrates displayed v ariation in thermal properties evidenced by Differential Scanning Calo rimetric analysis and significant differences in IR absorption spectra , accounted for by the different bonding of mater in the crystal latti ce. Identity of IR spectra of the forms obtained by dehydration (in in ert atmosphere at 100 degrees C) of the samples as well as the study o f crystalline anhydrate have supported this statement.