Assay for etoposide in human serum using solid-phase extraction and high-performance liquid chromatography with fluorescence detection.

An HPLC assay for etoposide in human serum was developed. Serum, spiked with podophyllotoxin (internal standard), was treated with sodium dodecyl sulphate prior to solid phase extraction. Analysis was performed on a 300x3.9 mm Bondclone 10 C18 column coupled with a fluorometric detector (lambda(ex) 230 nm, lambda(em) 330 nm). The retention times for etoposide and podophyllotoxin were 14 and 28 min respectively. The range of assay was 0.5 to 20 microg/ml with a detection limit of 0.2 microg/ml. This assay is suitable for use in clinical studies with etoposide.