Investigation of Iron Complex Formation of Anti-Hypertensive Drug: Methyldopa

The drug administered for any disease may play an unwanted function in biological system. They may have multiple counter effects, one of which is their interaction to bioactive metals. Iron is most common bio essential metal and is reported to interact with antihypertensive drug methyldopa. In the present study, above said complex is analyzed by UV-Visible spectrophotometry. Formation constant of the complex is calculated by using mole ratio method and single point statistical method which is in the range of 1010, values are also calculated which are independent of pH like formation constant. Absorbance maxima were found to be dependent on pH. At lower pH complex shows two broad bands centered at 430 nm and 730 nm. With the rise in pH later peak shifts toward lower wavelength, so 615 nm is selected for further studies. Molar extinction coefficient of the complex is explored by serial dilution method. At all wavelengths it increases with increase in pH. Mole ratio and slope ratio methods are used for exploring stoichiometry. Metal to ligand combining ratio in the complex is 1:2 at pH 4.0 and pH 4.5 while 1:3 at pH 5.0 and pH 5.5.