erapamil hydrochloride characterization was performed using TG, DSC and IR. TG curves
(TGA50H Shimadzu thermobalance). Conditions used were heating rate 10 °C/min, from room
temperature up to 750 °C, nitrogen flow rate 50 mL/min, with a mass of 5.0 mg in an alumina crucible.
DSC curves (DSC50 Shimadzu calorimeter) were obtained under nitrogen flow rate 50 mL/min,
heating rate 10 °C/min from room temperature up to 400 °C. The aluminum crucible was partially
closed with about 0.5 mg of sample. The assessment of purity by DSC was made by Van't Hoff
equation using the Shimadzu Purity Determination Program Software, version 2.20. The DSC and TG
temperature axes were calibrated with indium (99.99%; melting point, 156.60 °C) and by the Curie
point of Ni (353 °C), respectively, heated at the same rates used for the samples.