Binding Affinity of Synthetic Cannabinoids to Human Serum Albumin: Site Characterization and Interaction Insights

Background/Objectives: High-performance affinity chromatography (HPAC) was used to investigate the binding affinity of a series of synthetic cannabinoids, a widely abused class of new psychoactive substances, to human serum albumin (HSA) and obtain insights into the binding sites. To better understand the recognition mechanisms, molecular docking studies were conducted. Methods: Binding affinity was assessed through zonal elution approach Additionally, displacement chromatography with site-specific probes provided insights into the HSA binding sites of five synthetic cannabinoids. Results: That these drugs exhibit extensive binding to HSA, with values ranging from 98.7% to 99.9%. Competition for site I was observed between warfarin and four synthetic cannabinoids (5F-AMB, AB-PINACA, AMB-FUBINACA, and AB-CHMINACA). Furthermore, AB-CHMINACA also competed with L-tryptophan for site II. The binding affinity of all synthetic cannabinoids increased in the presence of (S)-ibuprofen. Molecular docking studies supported the experimental findings, reinforcing the insights gained. Conclusions: The key novelty of this study lies in analyzing, for the first time, the binding affinity of synthetic cannabinoids to HSA through HPAC and molecular docking. These results may improve our understanding of their toxicokinetic behavior and help in predicting possible competitive interactions that could influence HSA binding and, consequently, their activity and toxicity. This study is the first to describe the binding affinity of synthetic cannabinoids to HSA, elucidate their recognition mechanisms, identify binding sites, and characterize their interactions with the protein.