THE NEW INHIBITORS OF RIBONUCLEOTIDE REDUCTASE - COMPARISON OF SOME PHYSICOCHEMICAL PROPERTIES

Amidox (AX), didox (DX) and trimidox (TX), compounds synthetized as ne w ribonucleotide reductase inhibitors, have been investigated by ultra violet (UV) spectrophotometry, polarography and high performance liqui d chromatography (HPLC). The experiments have been performed at variou s pH values. The changes in UV absorption of the compounds studied wer e recorded and it was demonstrated that these changes are related to t he pH and to structural features of the investigated molecules. From t he compounds included in our series of experiments, only amidox and tr imidox are reduced during polarographic experiments in Britton-Robinso n buffer. The reduction of both compounds proceeded in two one-electro n steps in acidic pH. One two-electron diffuse irreversible wave was o bserved at basic pH. The values of the half-wave potential became more negative in accordance with the increasing pH. HPLC assay also showed changes in the retention of compounds investigated: particulary when the pH of the mobile phase was close to the dissociation constant of t he particular drug. The changes of physico-chemical properties detecte d by the all used methods are related to different chemical structures (the most significant changes were observed in alkaline pH). (C) 1997 Elsevier Science B.V.