Photo-degradation study of dacarbazine by spectrophotometric-chemometrics and HPLC methods

DTIC or dacarbazine is a photosensitive drug which is analyzed by chromatography methods. In this study, chemometric methods were applied to resolve the UV-Vis absorbance spectra recorded during irradiation of DTIC by an artificial lighting source. The photo-degradation reaction was monitored at different pH media (between 2 and 12). Multivariate curve resolution-alternative least square was then employed to simultaneously analyze the absorbance data matrices obtained at various pH media. Factor analysis revealed the presence of five chemical species co-existing in the reaction media. Regarding the analysis of concentration profiles of the detected species at different pH values, three species were attributed to the different acid-base states of DTIC, while the remaining components were considered as acid-base states of the photoproduct. Eventually, the presence of major photoproduct (2-azahypoxanthine) was confirmed by the HPLC method.