Simultaneous Determination of Prednisolone and Hydrocortisone in Serum by High-performance Liquid Chromatography
Qin Yongping;Yu Qin and Luo Zhigang (Institute of Clinical Pharmacology.West China University of Medical S610041)
A sensitive and specific method for the simultaneous measuremnet of both prednisolone (PL) and hydrocortisone (HC) in serum using dexamethasone (DX) as the internal standard was reported.High-performance liquid chrornatograph Model 344 (Beckman. USA) with a 254nm wavelength UV detector and YQG-80 silica column(5μm,250mm×4. 6mm)was used.Serum sample(0.5ml) was extracted with 2.5ml ethyl acetate and the organic layer was evaporated to dryness under an air stream in a 37℃ water bath,The residue was dissoved in 30μl mobile phase and 20μl injected. The mobile phase of methylene chloride and methanol ( 97: 3) was pumped at 2.0ml/min through the column.The detector was operated at 0. 002AUFS. The retention time for PL, HC and DX was 10.36,7. 63 and 6. 30min, respectively.Standard curve was linear in the concentration range of 0.03125 to 1. 0μ mol/L for both PL and HC.The detection limits in serum was 0.02μ mol/L for PL and 0. 012μ mol/L for HC.Extraction recovery was 81%～89%,within-day RSD was less than 4.5%.inter-day RSD was less than 8.5% for both PL and HC.