Design, characterisation, and phase transformation of a tranexamic acid–gallic acid cocrystal

Cocrystal engineering offers a promising strategy to enhance mechanical properties; however, it may also induce undesired crystal phase transformations during storage. This work aimed to improve the mechanical performance of tranexamic acid (TRA) by synthesising cocrystals with gallic acid (GA). The stability of the resulting cocrystals under accelerated conditions was further evaluated as a key indicator of long-term physicochemical reliability. Cocrystals were prepared using multiple formulation techniques, and their formation was confirmed by X-ray diffraction (XRD), thermal analysis, and morphological assessment. Compressibility and compactibility were also examined. Stability was assessed through changes in diffractogram patterns using XRD-based multivariate modelling, alongside variations in drug assay and antioxidant activity. The TRA–GA cocrystals produced by different preparation methods demonstrated improved tablet mechanical properties. The cocrystals under accelerated storage condition followed non-linear, logistic kinetic, behaviour in cocrystal transformation. Depending on the preparation method, the reduction of cocrystal content, drug assay, and antioxidant activity exhibited 6–35% variation.