Intermolecular interaction induced multi-polymers of aceclofenac with flexible conformation: Crystal structure, thermostability, solubility and DFT calculations

Abstract

The non-steroidal anti-inflammatory drug aceclofenac (ACF) has low bioavailability because of its poor water solubility. To enhance its water solubility we synthesized three compounds: a co-crystal of ACF- 0.5BIPY (4,4'-bipyridine) (1), a salt of ACF-3-ABA (3-aminobenzoic acid) (2), and a solvate of ACF-DMSO (dimethyl sulfoxide) (3). These compounds were characterized by infrared spectroscopy, powder and single crystal X-ray diffractions. The supramolecular structures of 1-3 are sustained by hydrogen bonding C―H…π and π…π stacking interactions and they have favorable thermal stabilities. Thermodynamically, DFT calculations revealed that the most stable conformation of ACF exists in compound 3 and this structure is more stable than 1 and 2. Furthermore, upon the formations of the co-crystal, the salt or the solvate the solubility of ACF improves significantly.