الخلاصة

Differential Pulse Polarographic (DPP) wave was measured for atenolol in phosphate buffer solution pH 7.4 with a concentration of 1.12 ×10-5 M at 37 C°, using hanging dropping mercury electrode HDME as a working electrode, the study found that atenolol is an electrical active agents and has E1/2 0.112 V, the important part of the polarographic study is the interaction between drug - receptors. Two amino acids cysteine and tryptophan were selected as receptors, based on literature. After formation of molecular complexes for drug-receptor, a positive displacement in the value of the half-wave potential was noted, which refers to increasing on the energy gap of HOMO-LUMO molecular orbital's of the drug. By linking to the thermodynamic Keq and kinetic behavior, the rate constants of the forward k1 and reverse k-1 reaction was calculated for atenolol–receptor molecular complexes and through the half-life time was calculated. Gibbs free energy was calculated which gave a negative value for all the molecular complexes under study as an indicator of the spontaneous interaction. The chemical affinity was also calculated which gave a positive result as an indicator of the high tendency of molecules to associated with each other. A computational study using Gaussian software, DFT- 6311G for the formation of molecular complexes of atenolol with receptors, gave an indicated for a significant agreement between the behavior of complexes in theoretical study and polarographic study, depending on the value of the energy gap between the molecular orbitals HOMO-LUMO.