Hydrocortisone succinate and hydrocortisone simultaneously determined in plasma by reversed-phase liquid chromatography, and their pharmacokinetics in asthmatic children.

Hydrocortisone succinate and hydrocortisone are chromatographed with a mobile phase consisting of sodium acetate/acetonitrile (77/23, by vol), the effluent being monitored at 254 nm. p-Hydroxybenzoate-N-propyl is used as the internal standard. Detection limits are 0.5 mg/L for hydrocortisone succinate, 0.2 mg/L for hydrocortisone. For five different concentrations the respective mean analytical recoveries were 88.2% and 100.5%, the mean intra-assay CVs for slope 3.9% and 2.1%, and the inter-assay CVs 3.3% and 1.6%. Simultaneous measurement of hydrocortisone and its succinate ester may be useful for pharmacokinetic study. Concentration-time profiles for plasma after administration of hydrocortisone sodium succinate are presented.