Recrystallization of a pharmaceutical compound using liquid and supercritical antisolvents

Sulfabenzamide was recrystallized from its solutions by using liquid and supercritical fluid as antisolvents. The drug compound was dissolved in various organic solvents, such as acetone, methanol, ethanol, and ethyl acetate, and the solutions came into contact with two antisolvents, water (liquid) and carbon dioxide (supercritical fluid). Variations of the habit, particle size, and the thermal behavior of the crystals were examined to investigate the effect of the operating temperature, type of solvent and antisolvent, mixing method, and the presence of ultrasound. Crystal habits Such as acicular, Columnar, prismatic, equant, and tabular were obtained depending on the solvents and antisolvents used. Larger crystals with a broader distribution were produced at higher temperatures, and crystal size was reduced when the solution was sonicated while precipitation occurred. The variations of crystal size were correlated with the use of solubility parameters of solvents and antisolvents. The thermal analysis of crystals revealed that the types of solvent and antisolvent employed in crystallization have influenced the internal structure of the resulting crystals and produced different polymorphs of sulfabenzamide.