Effect of polyethylene glycol 4000 on dissolution properties of sulfathiazole polymorphs.

The dissolution rates of the two polymorphic forms of sulfathiazole containing polyethylene glycol 4000 were significantly different in water. The effect of agitation on the dissolution rates also was studied. At higher stirring speeds, the dissolution rates of the stable form were affected more than the metastable form. A high concentration of polyethylene glycol 4000 seemed to affect the dissolution properties of the metastable polymorph more than the stable polymorph.