The objective of this work is to study the effect of magnetic field (52 mT) on the interaction between two drugs, amlodipine and propranolol, with human serum albumin (HSA) in physiological buffer (pH 7.4) making use of UV absorption and fluorescence and circular dichroism (CD) spectroscopy. The binding constants (K), binding capacities (g) and Hill constants (nH) of the reactions were determined. The results showed that the binding parameters are different in the absence and presence of the magnetic field. The CD spectroscopy revealed that amlodipine induces an increase and propranolol a decrease of α-helix content of HSA. In this case, the application of magnetic field, also, brings about a small change in the CD spectra. The binding distance, r, between donor (HSA) and acceptors (amlodipine and propranolol) was obtained according to Förster theory of non-radiation energy transfer. These results suggest that the magnetic field affect mostly on the function of HSA such as drug binding, which plays a key role in drug distribution in the body, and slightly on the structure of HSA.

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