4. Conclusions
Hb plays a crucial role in the transport and deposition of a large
number of endogenous and exogenous substances like fatty acids,
drug molecules, amino acids, metals, etc. [29,30]. Therefore, identification
of the interaction between a drug and hemoglobin in human
metabolism is very important for pharmacokinetic studies of the common
drugs. In this study, a combination of spectrofluorometric and
thermal gravimetric methods was described in order to identify the interaction
of Hb with Tbz on magnetic nanoparticles. Tbz was interacted
with hemoglobin on the GPTS modified SPIONs at different temperatures.
Fluorescence spectroscopy allowed estimating the binding of
the drug via its fluorescent character. Therefore, thermodynamic parameters
such as ΔG, ΔH and ΔS were determined by using Stern–
Volmer and van't Hoff equations. ΔG was negative at all experimental
temperatures, which means that the reaction carried out spontaneously.
The positive values of ΔH and ΔS suggested that hydrophobic interactions
have a major role in the binding process according to the van't
Hoff equation via fluorescence measurements. The stabilities of Hb–
GPTS–SPIONs and Tbz–Hb–GPTS–SPIONs were also explained and the
kinetic parameters (E⁎, ΔH⁎, ΔS⁎ and ΔG⁎) were evaluated using the
Horowitz–Metzger method.