Development and validation of a stability-indicating reversed-phase high performance liquid chromatography method for assay of betamethylepoxide and estimation of its related compounds

Betamethylepoxide (16β-methyl-Δ1,4-pregnadiene-9β-11β-oxide-17α,21-diol-3,20-dione) is a key intermediate for the synthesis of various active pharmaceutical ingredients (APIs) of steroid compounds. A stability-indicating reversed-phase HPLC method for assay of betamethylepoxide and estimation of its related compounds has been developed and validated. This method can accurately quantitate betamethylepoxide in the presence of numerous structurally related compounds (including the α-epimer, known as alphamethylepoxide). This method can also adequately separate most of the impurities from each other and estimate their quantities in betamethylepoxide samples. The stability-indicating capability of this method has been demonstrated by adequate separation of the degradation products from betamethylepoxide in stress degraded and aged stability samples. The HPLC column used in the method was a 5 cm YMC Hydrosphere C18 column (4.6 mm I.D.) and the mobile phase consisted of (A) water and (B) acetonitrile:methanol (8:25, v/v).