IDENTIFICATION OF IMPURITIES IN THE PHARMACEUTICAL SUBSTANCE LS-1269 BY HPLC-MSMS

Abstract

The N.N. Blokhin Oncology Research Center synthesized indolo[2,3-a]carbazole N-glycoside, which received the laboratory cipher LСS-1269, which showed a pronounced antitumor effect during research.. During the study of LСS-1269 by HPLC, the presence of two impurities was revealed, called LСS-1269-X and LСS-1269-Y (impurities X and Y). The electronic absorption spectrum (EAS) of the impurity peak X was similar to the EAS of the indolo[2,3-a]carbazole N-glycoside obtained and described earlier under the laboratory cipher LCS-1208, and the EAS of the impurity was the spectrum of LCS–1269, which indicates that the impurities belong to indolo[2,3-a]carbazoles. In this regard, it is suggested about the structure of these impurities: impurity X is a xyloside of aglycone similar in structure to aglycone LCS-1208, which can be formed as a by-product at one of the last stages of the synthesis of LCS-1269, and impurity Y has the structure of triacetyl ester LCS-1269, which is a precursor of LCS-1269 in the synthesis process. The aim of the work was to identify impurities in the substance LHS-1C69, to confirm their structures and belonging to derivatives of indolo[2,3-a]carbazole. The identification of impurities in the substance LCS-1269 was carried out using the HPLC-MSMS method. For this purpose, X and Y impurities having the assumed structures were obtained by directed counter synthesis, which were used as reference samples. Comparison of peak retention times on extracted ion chromatograms (XIC) and MSMS spectra of impurities with XIC and MSMS spectra of samples of comparison of the alleged impurities confirmed their structure. As a result of the work carried out, the structures of impurities X and Y were identified and the affiliation of these impurities to derivatives of indolo[2,3-a]carbazole was confirmed.