Oxaprozin Analogues as Selective RXR Agonists with Superior Properties and Pharmacokinetics.

The retinoid X receptors (RXR) are ligand-activated transcription factors involved in multiple regulatory networks as universal heterodimer partners for nuclear receptors. Despite their high therapeutic potential in many pathologies, targeting of RXR has only been exploited in cancer treatment as the currently available RXR agonists suffer from exceptional lipophilicity, poor pharmacokinetics (PK), and adverse effects. Aiming to overcome the limitations and to provide improved RXR ligands, we developed a new potent RXR ligand chemotype based on the nonsteroidal anti-inflammatory drug oxaprozin. Systematic structure-activity relationship analysis enabled structural optimization toward low nanomolar potency similar to the well-established rexinoids. Cocrystal structures of the most active derivatives demonstrated orthosteric binding, and in vivo profiling revealed superior PK properties compared to current RXR agonists. The optimized compounds were highly selective for RXR activation and induced RXR-regulated gene expression in native cellular and in vivo settings suggesting them as excellent chemical tools to further explore the therapeutic potential of RXR.

Manganese(II) coordination compounds of carboxylate non-steroidal anti-inflammatory drugs.

Upon the interaction of MnCl2 with the non-steroidal anti-inflammatory drugs oxaprozin or flufenamic acid in the presence of the nitrogen-donors 2,2'-bipyridine or 1,10-phenanthroline as co-ligands, one dinuclear and two trinuclear Mn(II) complexes were isolated. The complexes were characterized by diverse techniques. The complexes were evaluated for their scavenging activity against free radicals such as hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid). The in vitro binding affinity of the complexes to calf-thymus (CT) DNA and serum albumins was also monitored. In total, we may suggest that the complexes present promising scavenging activity against the radicals tested, and they may bind to CT DNA via intercalation and reversibly to serum albumins.

Zinc-oxaprozin compounds: Synthesis, structure and biological activity.

Four novel zinc complexes, namely [Zn(oxa)2(MeOH)4] (1), [Zn(oxa)2(H2O)(bipy)]·MeOH·2.5H2O (2·MeOH·2.5H2O), [Zn(oxa)2(bipyam)]·1.25MeOH (3·1.25MeOH) and [Zn(oxa)2(phen)] (4), with the non-steroidal anti-inflammatory drug oxaprozin (Hoxa) and a N,N'-donor heterocyclic ligand, such as 2,2'­bipyridylamine (bipyam), 1,10­phenanthroline (phen) or 2,2'­bipyridine (bipy), were characterized with physicochemical techniques, various spectroscopies and single-crystal X-ray crystallography. In these coordination compounds, the oxaprozin ligands are coordinated to zinc ion in a monodentate or a bidentate chelating binding mode. The antioxidant activity of the complexes was evaluated via their ability to scavenge in vitro 1,1­diphenyl­2­picrylhydrazyl, hydroxyl and 2,2'­azinobis­(3­ethylbenzothiazoline­6­sulfonic acid) radicals. The complexes bind to calf-thymus DNA via intercalation as suggested via a series of studies employing UV-vis spectroscopy, DNA-viscosity measurements and competition with ethidium bromide. The complexes may bind to serum albumins tightly and reversibly in order to get transferred through the bloodstream.