Interaction of SZV 1287, a novel oxime analgesic drug candidate, and its metabolites with serum albumin

SZV 1287 is our novel multi-target analgesic, which seems to be a promising drug candidate for the treatment of neuropathic pain. Therefore, the drug development process has been started in 2016. Since the pharmacokinetic characterization of a drug candidate is essential and albumin binding of drugs can strongly affect their pharmacokinetic properties, herein we provided the detailed investigation and characterization of the interaction of SZV 1287 and its known metabolites with serum albumin. In a preliminary animal study, we demonstrated the appearance of SZV 1287, oxaprozin, L 2799, L 2805, and L 2811 in the circulation after the per os administration of the parent compound to rats. Then albumin-ligand interactions were examined employing fluorescence spectroscopy, affinity chromatography, ultrafiltration, ultracentrifugation, and molecular modeling. Finally, we tested the potential species dependent differences in the albumin binding of SZV 1287, employing human, bovine, porcine, and rat serum albumins. Our results demonstrated that SZV 1287 and its metabolites form highly stable complexes with albumin (Ka = 105 to 106 L/mol). Furthermore, SZV 1287 occupies Sudlow’s Site II on human serum albumin. Therefore, it is reasonable to hypothesize that SZV 1287-albumin interaction is an important issue regarding the pharmacokinetics of this drug candidate.