Densitometric determination of conjugated oestrogens in the raw material and in pharmaceutical preparations

A densitometric method for determination of complex mixtures of conjugated oestrogens in raw material and tablets was developed. The proposed procedure comprised hydrolysis of sodium sulphate esters of oestrone, equilin, 17 alpha-oestradiol, equilenin, 17 alpha-dihydroequilin and 17 alpha-dihydroequilenin, the chloroform extraction of free oestrogens and methyltestosterone (internal standard) and separation on TLC plates using chloroform-cyclohexane-dioxane-triethylamine (4.5:4.1:0.6, v/v) as the solvent for development. Quantitative assay was achieved by direct scanning of the oestrogen spots at 280 nm. The proposed method is simple, rapid, reproducible and adequate to control the content of conjugated oestrogens in the raw material and in pharmaceutical preparations.