This study aimed to determine the three-dimensional structure, scale-up process, and investigate the stability, potency, and anti-inflammatory profile of a new multicomponent salt, levofloxacin-flufenamate, abbreviated as LFN-FA. Initially, the molar ratio stoichiometry was screened, and the single crystal was prepared by slow evaporation. Single-crystal X-ray diffractometry (SCXRD) was used to determine the three-dimensional structure. Subsequently, the scale-up process was conducted using wet-grinding and hot-melting techniques to produce samples for stability, solubility, potency, and anti-inflammatory tests. SCXRD data proved that the multi-component structure of LFN-FA was a hydrated salt, consisting of the ionized carboxyl group of flufenamic acid and the amine group of levofloxacin, with a water molecule in a (1:1:1) molar proportion. Furthermore, scale-up by wet grinding successfully produced the anhydrous salt beside the LFN-FA hydrate, which both were physically stable under the open container conditions at room temperature (25-30 °C/ 75-85 %RH) for 4 weeks. They increased the solubility of flufenamic acid, with the anhydrous form demonstrating twice the solubility of the hydrate form. Hence, anhydrous LFN-FA was selected for evaluation of its chemical stability, in-vitro antimicrobial potency, and anti-inflammatory effect, all of which met the expected improvements. These experiments showed that this unique antibiotic-anti-inflammatory combination, LFN-FA, in a multi-component salt structure, could be developed further in the dosage form formulation.
