title: Determination of 9-nitrocamptothecin by precolumn derivatization and its metabolite 9-aminocamptothecin in a biological fluid using reversed-phase high-performance liquid chromatography with fluorescence detection.
abstract: A novel insoluble topoisomerase I inhibitor, 9-nitrocamptothecin (9-NC), is in advanced stages of clinical development and has been used to treat a diverse array of tumor types, including breast, ovarian, pancreatic and haematological malignancies. We have established a sensitive high-performance liquid chromatography method using fluorescence detection for the quantitation of 9-NC. Non-fluorescent 9-NC is converted to fluorescent 9-aminocamptothecin (9-AC) via a one-step pre-column derivative reaction. The quantitative limit of 9-NC was 1 ng/ml and the method was reproducible with the respective intra- and inter-day variability falling below 5.0 and 9.0%. The determination of both 9-NC and its metabolite 9-AC in dog plasma was also achieved using the same chromatographic and detection conditions. In dog plasma, the quantitative limits of 9-AC and 9-NC were 0.25 and 1 ng/ml, respectively. The presence of 9-AC in the samples yielded no interference with the determination of 9-NC. However, individual matrices can affect the conversion efficiency of 9-NC, thus indicating that standard samples should be run for each matrix.
authors.affiliation: Tigen Pharmaceutical, Inc., 235 Bolivar Street, Lexington, KY 40508, USA.
authors.forename: Junhong
authors.initials: J
authors.lastname: Zhang
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Burke
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Latus
mesh_terms: D000818:Animals; D002138:Calibration; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004285:Dogs; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: C079905:rubitecan; D002166:Camptothecin