RADICAL CHEMISTRY OF THE ANTITUMOR DRUG PAZELLIPTINE (PZE) IN AQUEOUS-SOLUTION OR INTERCALATED IN POLY(DA)-POLY(DT)

The effect of 2 ns pulse of 355 nm laser light on aqueous solutions of free pazelliptine (PZE) at different pH and complexed with poly(dA)-p oly(dT) was investigated. Spectral analysis revealed the occurence of a photoionization process generating PZE radical cation (PZE(.+)), and the formation of PZE triplet state. The absorption spectrum of the ra dical PZE(.+) was pH dependent and closely related to the protonated f orm of PZE in the ground state. Its kinetic evolution appeared very si milar for the free drug and for the intercalated complex. By contrast, the triplet state desactivation was different for the free drug and t he intercalating complex in deaerated solution. An electron transfer f rom the poly(dA)-poly(dT) was observed.