Analysis of CP-122,288 at femto-molar levels from human plasma using solid-supported extraction and HPLC column switching

A sensitive and specific method for the analysis of CP-122,288 in plasma ha s been developed and validated using column-switching HPLC with fluorescenc e detection. Solid-phase extraction (SPE) cartridges (Chem-Elut) are used t o extract analyte and internal standard from human plasma samples. The extr acts are analysed by heart-cutting from one analytical HPLC column to a sec ond column with fluorescence detection using excitation and emission wavele ngths of 225 and 350 nm respectively after post column UV irradiation at 25 4 nm. The method has a lower limit of quantification (LLOQ) of 10 pg mL(-1) and is linear over a fifty-fold range, vp to 500 pg mL(-1). An internal st andard (CP-122,638) is used which is a close chemical analogue of the compo und. This validated method has been used extensively for the analysis of CP -122,288 in plasma samples from clinical trials.