Prediction of 99mTc-biguanide complex structures and their interactions with biological molecules by molecular mechanics calculations.

The structures of some Tc-biguanide complexes are predicted by molecular mechanics calculations. In addition, simulations of molecular interactions between the predicted equilibrium structures with water molecules or peptide chains are correlated with experimental data of partition coefficients and percentage of human protein binding, evaluated for the analogous 99mTc-biguanide complexes. These results suggest the value of computer-assisted design of new Tc-radiopharmaceuticals, and in particularly, stress the great interest of using molecular modelling to predict molecular properties that can be successfully correlated with results obtained by in vitro studies.