Changes in the proportions of an active pharmaceutical through cocrystals.

In this study, the modulation of amounts sulfathiazolium cations in different 2,6‐pyridinedicarboxylates is demonstrated. An uncommon monoionic sulfathiazolium zinc 2,6‐pyridinedicarboxylate (1:1 electrolyte) complex was characterized. Conventional sulfathiazolium zinc‐bis‐2,6‐pyridinedicarboxylate dianionic complexes (2:1 electrolyte) were formed when hydroxyaromatic compounds such as 1,3‐dihydroxybenzene or 3‐nitrophenol were used as guest components. Thus, with the aid of the hydroxyaromatic molecules the zinc‐bis‐2,6‐pyridinedicarboxylate complexes were stabilized with the relatively large sized sulfathiazolium cations. It was a consequence of domain expansion by the phenolic compounds. Sandwiched aromatic guests between the 2,6‐pyridinedicarboxylates provided appropriate packing to accommodate the two large cations in the self‐assemblies, which helped to modulate the amounts of sulfathiazole in different formulations. Antibacterial activities with E. coli DH5α have shown that the salt and the complexes have lower g/ml antibacterial activity than the parent drug. [ABSTRACT FROM AUTHOR]