Gas chromatographic determination of glucocorticoids as trimethylsilyl ether derivatives (author's transl)

Abstract

Glucocorticoids, e.g., dexamethasone (DM), fluocinolone acetonide (FA), triamcinolone acetonide (TA), cortisone (CS), and corticosterone (CST), were determined by gas chromatography including trimethylsilylation. In method A, a solution of 5-50 μg of each glucocorticoid and 5 μg of cholesterol as an internal standard dissolved in 0.2 ml of N, O-bis (trimethylsilyl) acetamide (BSA) or N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) containing 5 mg of sodium acetate was heated at 60-80°for 2-3 hr. Two μl of the solution was analyzed by gas chromatography. In method B, 20 μl of the solution obtained in method A was transferred to a sample tube, evaporated under a stream of nitrogen, and the residue dissolved in 40 μl of carbon tetrachloride, 2 μl of which was analyzed by gas chromatography. FA was determined by method A, and DM, TA, CST, and CS by method B. Method B was applied to commercial DM tablets, and the results were compared with those obtained by UV and BT methods. The values by method B were lower than those by UV method, and were almost the same as those by BT method. The trimethylsilyl derivative of DM was proved to be a tetratrimethylsilyl compound by gas chromatography-mass spectroscopy.