The inhibiting effect of Esomeprazole Magnesium Trihydrate drug on the corrosion of mild steel (MS) in 1 M HCl was performed by chemical tests (weight loss (WL)) and electrochemical methods (Tafel polarization (TP), electrochemical frequency modulation (EFM) and AC impedance spectroscopy (EIS)). The adsorption isotherm of Esomeprazole Magnesium Trihydrate drug on the MS surface was found to follow Temkin adsorption isotherm. Some thermodynamic parameters were computed and discussed. The obtained data showed that the inhibition efficiency (IE) rises with increasing the dose of the Esomeprazole Magnesium Trihydrate and with raising the temperature. The morphology of MS surface was analyzed by using scanning electron microscope (SEM), atomic force microscopy (AFM), and Fourier transforms infrared spectroscopy (FTIR) techniques. All test methods were in good agreement with each other.

Expired nizatidine drug (END) was studied as inhibitor for α-brass in 1M HCl utilizing weight loss (WL), and electrochemical methods namely, AC impedance (EIS), Potentiodynamic polarization (PP), and electrochemical frequency modulation (EFM) tests. The protection efficiency (%IE) was improved with raising in the dose of the expired nizatidine and decreases with raising the temperature. The (%IE) reaching maximum value 95 % at higher dose of expired nizatidine drug at 25 o C. PP data indicated that nizatidine drug behaves like a mixed kind drug. The protection of α-brass corrosion by nizatidine can fit to the adsorption ability of nizatidine drug molecules onto the reactive sites of the α-brass surface. The adsorption of the drug follows Langmuir adsorption isotherm. The surface morphology of α-brass was investigated. The results obtained from different methods are in excellent agreement.