Simultaneous determination of corticosterone, hydrocortisone, and dexamethasone in dog plasma using high performance liquid chromatography.

A sensitive, specific and reproducible high-performance liquid chromatographic procedure, using the normal phase and radial compression system, is described for the simultaneous determination of corticosterone, hydrocortisone, and dexamethasone in plasma, with prednisolone as the internal standard. Samples were extracted with methylene chloride and chromatographed on a microparticulate silica gel column using a radial compression system with UV detection at 254 nm. The assay has been applied in pharmacokinetic studies, and a typical plasma concentration-time profile for three corticosteroids (all with 2 ng/ml sensitivity) is presented for dogs receiving dexamethasone.