Pharmaceutical Salts of Piroxicam and Meloxicam with Organic Counterions

Shan Huang; Dean S Venables; Simon E Lawrence

doi:10.1021/acs.cgd.2c00722

Pharmaceutical Salts of Piroxicam and Meloxicam with Organic Counterions

Cryst Growth Des. 2022 Oct 21;22(11):6504-6520. doi: 10.1021/acs.cgd.2c00722. eCollection 2022 Nov 2.

Authors

Shan Huang¹, Dean S Venables², Simon E Lawrence¹

Affiliations

¹ School of Chemistry, Analytical and Biological Chemistry Research Facility, Synthesis and Solid State Pharmaceutical Centre, University College Cork, Cork T12 K8AF, Ireland.
² School of Chemistry and Environmental Research Institute, University College Cork, Cork T12 K8AF, Ireland.

Abstract

Piroxicam (PRM) and meloxicam (MEL) are two nonsteroidal anti-inflammatory drugs, belonging to the Biopharmaceutics Classification System Class II drugs. In this study, six novel pharmaceutical salts of PRM and MEL with three basic organic counterions, that is, 4-aminopyridine (4AP), 4-dimethylaminopyridine (4DMP), and piperazine (PPZ), were prepared by both slurrying and slow evaporation. These salts were characterized by single-crystal and powder X-ray diffraction, thermal analysis, and Fourier transform infrared spectroscopy. All six salts, especially MEL-4DMP and MEL-4AP, showed a significantly improved apparent solubility and dissolution rate in sodium phosphate solution compared with the pure APIs. Notably, PRM-4AP and PRM-4DMP salts exhibited enhanced fluorescence, and the PRM-PPZ salt showed weaker fluorescence compared with that of pure PRM due to different luminescence mechanisms.