Factor analysis of excitation fluorescence spectra of camptothecin and its analogue: DB-67

The fluorescence excitation spectra of camptothecins -- alkaloids which have anticancer properties, are analyzed in this paper. Camptothecins exist in two forms -- biologically active lactone form and inactive carboxylate form. In fluids of pH 7,4 lactone forms hydrolyze and convert into carboxylate forms. There are some differences in shapes between fluorescence excitation spectra of lactone and carboxylate forms. One can observe evolution of fluorescence spectra during hydrolysis of camptothecins. Using principal component analysis and factor analysis to the set of fluorescence spectra recorded during process of hydrolysis of camptothecins one can determine the temporary concentration of lactone and carboxylate forms in solutions of pH 7,4 and obtain kinetics of deactivation of this compounds.