Chromatographic analysis and decomposition product characterization of compound SR16157 (NSC 732011)

SR16157 (21-(2-N,N-diethylaminoethyl)oxy-7alpha-methyl-19-norpregna-1,3,5(10)-triene-3-O-sulfamate) is a novel, dual-acting estrone sulfatase inhibitor currently in preclinical development for use in breast cancer therapy. The compound has a dual mechanism of action: the sulfamate-containing parent compound SR16157 inhibits estrogen biosynthesis by irreversibly inhibiting the enzyme estrone sulfatase. The phenolic metabolite, SR16137, generated by the sulfatase enzyme is a potent antiestrogen in breast tissues and has beneficial effects in bone and the cardiovascular system. As part of the ongoing preclinical studies, an HPLC assay method has been developed and validated for SR16157. The assay method is specific, accurate (recovery=99.4-101.1), linear (r(2)> or =0.9999), precise (intraday R.S.D.< or =1.1%, intermediate R.S.D.< or =0.8%), and sensitive (limit of detection=1.0 microg/ml). It separates SR16157 from its impurities and forced decomposition products, which have been characterized by LC coupled with mass and UV spectral data. Major decomposition pathways are hydrolysis, hydroxylation, and oxidation.