New salt-solvates of Mirabegron: a combined experimental and computational study†

A comprehensive combined virtual and experimental multicomponent solid-form screening has been carried out for Mirabegron, a therapeutic agent widely prescribed for interstitial cystitis and bladder pain syndrome. This systematic approach resulted in the identification and structural elucidation of three novel salt/solvate forms using single-crystal X-ray diffraction (SCXRD). These include two distinct mirabegron–orotate salts (1a and 1b) and a mirabegron–isobutyrate (acetonitrile solvate) salt (2). A detailed Density Functional Theory (DFT) computational analysis unveiled a diverse array of intermolecular interactions in these newly characterized forms, some of which were not observed in the elusive crystal structure of Mirabegron previously reported in the literature. These interactions, essential for understanding the stability and properties of the solid forms, have been meticulously evaluated both structurally and energetically. Advanced computational tools, including Quantum Theory of Atoms in Molecules (QTAIM), non-covalent interaction (NCIPlot) analysis, and Molecular Electrostatic Potential (MEP) surface mapping, were employed to provide in-depth insights into the nature and strength of these interactions, further enriching the understanding of Mirabegron's solid-state chemistry.