Binding studies of lincosamide antibiotic drug clindamycin phosphate to human serum albumin by fluorescence, 3D, and circular dichroism spectroscopy

Abstract

The binding interaction between clindamycin phosphate and human serum albumin (HSA) has been studied by multiple spectroscopic techniques. The binding constants at three temperatures (288, 298, and 308 K) were 2.12, 3.74, and 6.95 × 104 dm3 mol−1 , respectively, and the number of binding sites were 1.15, 1.18, and 1.22, respectively; thermodynamic parameters ΔH o (43.76 kJ mol−1), ΔG o (−20.460 kJ mol−1), and ΔS o (215.50 J K−1 mol−1) were calculated. The distance r between donor and acceptor was obtained (r = 6.37 nm) according to the Forster theory of non-radiative energy transfer. In addition, synchronous fluorescence spectroscopy, circular dichroism, and 3D fluorescence spectroscopy showed that the binding of clindamycin phosphate to HSA changed the secondary structure of the protein.