Abstract
This study investigates the binding interactions between bovine serum albumin (BSA) and camptothecin (CPT) drugs (camptothecin, 10-hydroxycamptothecin, topotecan, and irinotecan) using UV-Vis spectroscopy, fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, and molecular docking techniques. The fluorescence quenching of BSA by CPT drugs follows a static mechanism, with binding constants (K(b)) ranging from 4.23 × 10(3) M(- 1) (CPT) to 101.30 × 10(3) M(- 1) (irinotecan), demonstrating significant drug binding selectivity. Thermodynamic analysis reveals distinct interaction mechanisms: topotecan binding is driven by hydrogen bonding (ΔH = - 10.96 kJ·mol(- 1)) and hydrophobic interactions (ΔS = 0.066 kJ·mol(- 1)·K(- 1)), while irinotecan exhibits stronger binding dominated by electrostatic forces (ΔH = - 86.77 kJ·mol(- 1)) with significant entropy loss (ΔS = - 0.161 kJ·mol(- 1)·K(- 1)). Molecular docking confirms preferential binding at Sudlow site I of BSA, with hydrophobic interactions and hydrogen bonding as the primary driving forces. These findings provide a comprehensive understanding of CPT-BSA interactions, offering valuable insights for the design of albumin-based drug delivery systems with optimized pharmacokinetic profiles.