ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Dual optimization of antibacterial activity and dissolution performance: a novel gatifloxacin molecular salt

Ze Li

College of Ecological and Environmental Protection, Linyi Vocational University of Science and Technology, Linyi, China

E-mail: ylize@126.com

Received: 27 December 2025  Accepted: 23 March 2026

Abstract:

To improve the drug performance of the antibiotic gatifloxacin (GAT), a novel molecular salt was designed and synthesized using cinnamic acid (CIA), a phenolic acid nutrient with inherent antibacterial activity. This salt-forming strategy modifies the solid-state structure of GAT without altering its covalent framework, leading to enhanced physicochemical and antibacterial properties. The obtained GAT-CIA molecular salt was thoroughly characterized by single-crystal X-ray diffraction, thermal analysis, and powder X-ray diffraction. Structural studies revealed that proton transfer from CIA to the piperazine nitrogen of GAT generates a quaternary hydrogen-bonded motif, resulting in a two-dimensional layered architecture. Compared with pure GAT, the molecular salt exhibits significantly improved solubility, intrinsic dissolution rate, and membrane permeability, especially under neutral pH conditions. Furthermore, antibacterial assays demonstrated that GAT-CIA possesses stronger inhibitory activity against several bacterial strains, owing to the enhanced physiochemical property arising from the cocrystallization of GAT and CIA. This work provides a practical cocrystallization approach to simultaneously optimize the biopharmaceutical properties and antibacterial efficacy of fluoroquinolone antibiotics.

Graphic abstract

A novel molecular salt of the antibacterial drug gatifloxacin (GAT) with CIA has been assembled and systematically characterized. The results showed that both the physicochemical properties and antibacterial activities of GAT were improved.

Keywords: Gatifloxacin; Cinnamic acid; Molecular salt; Theoretical calculation; Pharmaceutical properties

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04839-w

Chemical Papers 80 (7) 7599–7612 (2026)