DSC study and calculation of metronidazole and clarithromycin thermodynamic melting parameters for individual substances and for eutectic mixture

•The system clarithromycin–metronidazole is a system with a simple eutectic.•The eutectic melting temperature for the system clarithromycin–metronidazole is 155.2 ± 0.5 °C and it is not changed by varying the composition of the system.•The DSC curve for the composition of 89:11 mol or 64.9:35.1 wt% corresponds to the eutectic (or the invariant) composition for the system clarithromycin–metronidazole.

In this study melting thermodynamic characteristics of clarithromycin and metronidazole as individual substances were investigated by DSC method. It was found that the binary system of clarithromycin and metronidazole is a system with simple eutectic. Composition, melting temperature and the heat of fusion of the eutectic were determined by calculation and experimental methods.