Cation-anion palladium complexes: the effect of the hydrogen bond character on their stability and biological activity

The results of study of a new class of biologically active palladium complexes (AH _n ) _m PdCl₄] have been reported. This class of compounds has been discovered by us on the basis of systemic research of composition-structure-biological activity relationships for different classes of platinum metal complexes. It has been shown that the stability of cation-anion palladium complexes and their biological activity are determined by the nature of protonated amines acting as cations and the acid-base properties of the cations-tetrachloropalladate anion systems, manifested in the character and stability of hydrogen bonds that appear in these systems. For the first time, it has been demonstrated in vivo that it is possible to synthesize palladium compounds superior to cisplatin in antitumor activity and not exhibiting immunosuppressive activity, as well as palladium compounds with immunostimulatory and radiomodifying activity. A combination of cytostatics used in oncology or irradiation with palladium complexes leads to significant synergism of their effects and to a considerably higher therapeutic efficiency of such combinations as compared with the treatment effect of each of them alone.