Spectroscopic Studies of the Interaction between Metformin Hydrochloride and Bovine Serum Albumin

Abstract

The affinity of a drug to serum albumin has influence on the pharmacokinetics of a drug. In the
present study, the mutual interaction of metformin hydrochloride (MET) with bovine serum albumin (BSA) was
investigated using fluorescence spectroscopy under different conditions. It was observed that the fluorescence
quenching of BSA by metformin hydrochloride is a result of the formation of metformin hydrochloride- BSA
complex with probable involvement of tryptophan residue. Fluorescence quenching constants were determined using
the Stern- Volmer equation and Van’t Hoff equation to provide a measure of the thermodynamic parameters ΔG, ΔH,
and ΔS at different temperatures indicating that the hydrogen bond and the hydrophobic forces play a major role for
metformin hydrochloride- BSA association.