A POTENTIOMETRIC STUDY OF METAL-ION COMPLEXES OF ANTINEOPLASTON A10, A NEW ANTITUMOR AGENT

3-(N-phenylacetylamino)-2,6-piperidinedione, Antineoplaston A10, is a new antitumour agent. In an attempt to explore its binding properties, the interaction of A10 with Ca(II), Mg(II), Cu(II), Zn(II), Co(II), N i(II), Hg(II) and Ag(I) ions was investigated by potentiometric method s. Stability constants of 1:1 complexes (ML) were determined in aqueou s methanol (50%, v/v) at 45.0 degrees C and 0.1 M (KNO3) ionic strengt h. It has been shown that complex formation is accomplished by release of a proton; binding with metal ions probably occurs at the deprotona ted nitrogen atom of the 2,6-piperidinedione ring. It is concluded tha t the coordinating properties of Antineoplaston A10 are similar to tho se of uracil and thymine.