A Drug–Drug Salt Hydrate of Norfloxacin and Sulfathiazole: Enhancement of <i>in Vitro</i> Biological Properties via Improved Physicochemical Properties

A new multicomponent solid consisting of an antibacterial (norfloxacin) and an antimicrobial (sulfathiazole) was made and characterized with single crystal X-ray diffraction, PXRD, FTIR, and DSC. The title salt shows enhanced solubility in different pH buffers and improved diffusion as well as release and inhibition of bacterial and fungal species relative to the parent drugs. The enhanced in vitro biological properties of the drug–drug salt hydrate may be attributed to the higher extent of its supersaturation with respect to the individual components, which leads to higher diffusion rates.