Exploration of new solid forms of anti-emetic drug domperidone: Novel salts with enhanced solubility and dissolution

Domperidone (DMP) is an anti-emetic agent used for treatments like dyspepsia, indigestion, epigastric pain, nausea, and vomiting. DMP belongs to BCS class II having poor aqueous solubility and high permeability. In the current work, nine novel salts of DMP with coformers namely acetic acid (ACA), oxalic acid (OXC), Fumaric acid (FMA), Glutaric acid (GLA), Adipic acid (ADA), Saccharin (SAH), Salicylic acid (SAL), 4-Hydroxybenzoic acid (4HBA), and Theophylline-7-acetic acid (THA) have been reported. The crystal structures have been determined by Single-Crystal X-ray Diffraction (SC-XRD). In the SC-XRD study, proton transfer from coformer to piperidine 'N' of DMP was observed in all the salts. The prepared salts were further characterized by spectroscopic (FT-IR), thermal (DSC and TGA), and Powder X-ray Diffraction (PXRD) techniques. The solubility study in purified water (pH=6.5) showed 127 and 51-fold enhancement in DMP-GLA and DMP-ACA salts. The salts namely, DMP-ACA, DMP-GLA, and DMP-SAL disintegrate to parent DMP after attaining equilibrium in water medium. In 0.1 N HCl medium, DMP-ACA, DMP-GLA, DMP-ADA, and DMP-4HBA exhibited a two-fold increment in solubility compared to DMP. The in-vitro dissolution study in purified water showed faster drug release in DMP-ACA, DMP-GLA, and DMP-ADA salts.