Development of the method for estimating complex formation using the electrochemical impedance spectroscopy on the example of the doxycycline and iron (III) interaction

The aim. To develop an EIS method for study the interaction between medicinal products and metal salts on example of Doxycycline iron (III) interaction.
 Materials methods. Measurements total impedance studied solutions have been performed using a vector circuit analyzer ZNB40 (Rohde & Schwarz, Germany). calculations electrical models were software package EC-Lab V10.40. Measurement cell was made Teflon, 1 ml volume, had 2 parallel nickel plated steel electrodes with diameter 6 mm, distance is 9 mm. Basic elements model calculated according to type electrochemical process that described by Nyquist plot (RW, Rct, RS, Cd, CS etc.). Solutions prepared immediately before measurement. at temperature 296±3 K. control doxycycline chloride measured. 11 molar ratio 1:6, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1 Concentration X∙10-3 mol/L respectively.
 Results. analysis curves in range ratios 1: 6, 5, 4, 3, 2, 1, 2: 3: 4: 5: 6: showed change dynamics resistance 1:1. In aqueous solution T = K constant formation hyclate 2.9. This value complexation indicates forms stable metal-ligand complex ions.
 Conclusions. can be applied products. Model this created chloride. Metal-ion these two molecules once again confirmed