The determination of nivacortol in plasma using HPLC

A high performance liquid chromatographic method with ultraviolet detection was developed for the determination of nivacortol (WIN 27914) in biological samples. The drug was isolated from human plasma by using a solid-phase extraction and eluted with ethanol. The solvent was evaporated and the residue dissolved in the chromatographic eluent. The sample was subjected to chromatography on a C8 silica column and eluted with a gradient of acetonitrile in 0.1 M sodium acetate buffer, pH 6.5. A single concentration of a structural analogue (WIN 31338) was used as internal standard for the quantitative determination of the analyte. The plasma concentrations were below that needed to suppress ACTH secretion by pituitary cells in culture and did not suppress plasma ACTH in Nelson's syndrome.