GLC determination of 17 alpha-ethynylestriol 3-cyclopentyl ether

A rapid, sensitive, and accurate GLC method of analysis of a new estrogenic drug, 17 alpha-ethynylestriol 3-cyclopentyl ether, was developed. The drug and the internal standard, tetratriacontane, are dissolved in chloroform, and an aliquot is heated with N-trimethylsilylimidazole at 80 degrees for 30 min. The silylated sample is chromatographed using a column packed with 1% methyl vinyl silicone gum on Gas Chrom Q. Quantitation is achieved by computer calculation of the peak area ratios. The observed peak is the 16alpha,17beta-bistrimethylsilyl derivative of the new drug substance. The GLC method was applied to the quantitative determination of the estrogenic compound in a tablet formulation containing 25 mug/tablet.