Application of differential scanning calorimetry to the study of sulphathiazole crystal forms

Abstract

Abstract Methods of preparation and characterization of two crystal forms of sulphathiazole using differential scanning calorimetry and infrared spectroscopy are described. Heats of transition and fusion calculated from thermal analysis are 1778±68 Cal mol−1 and 6615 ± 235 Cal mol−1 respectively. The transition temperature depends on the rate of heating and the sample source. Interconversion of the crystal forms under different conditions such as heating and suspension in water is described. An assay procedure based on the area of the thermal transition peak of Form I was devised and results of analysis of synthetic mixtures of Forms I and II are given.