Crystalline Cu(II)-AZM complex and its co-amorphous system: New antibiotic-based compound

Azithromycin (C38H72N2O12, AZM) is a half-synthetic macrolide synthetically obtained from the A erythromycin. It is the first member of a new family of antibiotics known as azalydes, showing some advantages other antibiotics due to its capacity of tissue penetration and higher stability in acidic media. To enhance the effect of the drug and expand the possibilities of application, complexes and solids dispersions involving transition metals or organic molecules have been synthesized over the last few years. In this context, two AZM compounds were synthesized, one in the crystalline form with hydrated copper (II) and the other in the amorphous form with copper (II) and tromethamine. Even if their structural, thermal, and vibrational properties have been characterized and analyzed, a complete description of the location of the water molecules in these systems s still missing. This is however essential to resolve open questions about the molecular packing, solubility, and bioavailability of the drug. Therefore, we propose to use TOSCA to investigate the intermediate intermolecular contacts by H2O molecules in the hydrated and amorphous system, and how they differ from each other.