Abstract
The supercritical antisolvent process was used to modify the solid state properties of sulfathiazole, chlorpropamide, and sulfamethizole. Acetone, methanol, ethyl acetate, and DMF were employed as solvents for the three pharmaceutical compounds and carbon dioxide was used as an antisolvent. The effects of process parameters on the precipitated crystals such as carbon dioxide injection rate, type of solvent, and temperature were investigated. The processed crystals showed more ordered appearances with clean surfaces and sharp angles compared with the unprocessed particles. The various crystal habits such as tabular, platy, acicular, and columnar were observed depending on the experimental conditions. The crystal habit changed from tabular to acicular when the antisolvent injection rate increased. DSC measurement revealed that the carbon dioxide injection rate affected the crystallinity of the drug particles. Larger crystals were consistently obtained at higher temperatures. The crystal size significantly increased when the nucleation and crystal growth took place at a slow rate.
