karbala journal of pharmaceutical sciences

Moleculer complxes of drugs (Warfarin and Thyroxine) with amino acids (Arginine and Tyrosine) were studied theoretically using PM3 Semi-empirical calculations of molecular orbital model and IR- techniques. The studied systems was: Warfarin with Arginine and Thyroxine with Tyrosine , The optimized geometry of the complexes showed interaction between drugs and Amino Acid molecules, the bending energies for these interaction varies from (- 4.194 to – 0.529) Kcal.mol-1. Which attributed to the formation of hydrogen bonding, and confirm experimentally by the IR- technique.