Effect of thermal history on the glassy state of indapamide

Abstract

The effects of thermal history, e.g. cooling rate, annealing, etc., on the thermal behaviour of indapamide glass were determined by differential scanning calorimetry (DSC). The glass was prepared by heating indapamide crystals (m.p. 162 °C) to 180 °C., and then cooling the melt to room temperature. The glass transition temperature (Tg) of the material was 98 °C. An endotherm, due to thermal relaxation of the glass, was observed in the DSC thermogram when indapamide glass was prepared by slow cooling or was annealed isothermally at a temperature below Tg. Such enthalpy relaxation may be observed during ageing of pharmaceutical glasses and might influence their physicochemical properties.