Three expired drugs, Solo Sept (SS), Slim-lax (SL), and Well Derm (WD), have been tested as corrosion inhibitors
for corrosion of copper alloy (C10100) in 2.0 M HNO3 solution. Three experimental methods such as weight loss
measurements, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) were
applied in this study. These expired drugs function as effective inhibitors, according to the experimental fndings.
The effcacy of inhibition rises with increasing drug concentration and falls as temperature rises. From PDP, the
examined drugs that worked as mixed-type inhibitors. EIS measurements showed a remarkable increase in the
charge transfer resistance and decreases in the capacity of the double layer of the corroding copper in 2.0 M
HNO3 solution with increasing drug concentration. The inhibition power of these drugs was interpreted in term
of its adsorption on the C10100 surface according to Langmuir isotherm. The inverse effect of temperature on
drug effciency as well as the small negative values of ΔG◦ads (-20.84, -20.52 and -20.51 kJ/mol) for SS, SL and
WD respectively, supports the physical adsorption of drugs on the C10100 surface. All results showed consistency
with IE order (SS > SL > WD). The adsorption thermodynamic functions were estimated. The corrosion inhibition performance of SS was confrmed through SEM (scanning electron microscope) and FTIR