Mechanistic and conformational studies on the interaction of anesthetic sevoflurane with human serum albumin by multispectroscopic methods

To know the interaction of sevoflurane with human serum albumin (HSA), techniques of different spectroscopies were used. Steady state fluorescence suggested a static type for sevoflurane-HSA interaction. On the basis of the thermodynamic results and site marker competitive experiments, it was considered that sevoflurane was bound to site I (subdomain IIA) of HSA mainly by electrostatic force. The calculated binding distance (r = 2.1 nm) indicated that the non-radioactive energy transfer came into being in the interaction between sevoflurane and HSA. Stem-Volmer plots were made and quenching constants (4.01 x 10(4) M-1 at 298 K) were thus obtained. Association constant at 298 K was 5.89 x 10(5) M-1 for the system, which could affect the distribution, metabolism, and excretion of the drug. In addition, three-dimensional fluorescence, circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy results showed that the binding of sevoflurane can cause conformational and some microenvironmental changes of HSA. Electrochemical techniques demonstrated the complex formation between sevoflurane and HSA. This paper provides reasonable models helping us further understand the transportation and distribution of sevoflurane when it spreads into human blood serum which is of great importance in pharmacology and pharmacodynamics. (C) 2017 Elsevier B.V. All rights reserved.