HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF BETAMETHASONE AND DEXAMETHASONE

A simple method was developed for the determination of glucocorticoid epimers of betamethasone (BTM) and dexamethasone (DXM) by high-perform ance liquid chromatography with UV detection, using silica as the stat ionary phase and dichloromethane-ethanol (34:1, v/v) as the mobile pha se. The linear range of the method for the determination of BTM and DX M in 1.0 ml of sample solution was over 5-50 nmol. The detection limit s (signal-to-noise ratio = 5) of BTM and DXM with an injection volume of 25 mu l were 80 and 60 pmol, respectively. The method was satisfact orily applied to the individual determination of BTM and DXM in commer cial tablets.