Application of a highly specific and sensitive fluorescent HPLC method for topotecan lactone in whole blood

K. ELAINE HUBBARD; PAULA SCHAIQUEVICH; FENG BAI; CHARLES H. FRAGA; LAURA MILLER; JOHN C. PANETTA; CLINTON F STEWART

BIOMEDICAL CHROMATOGRAPHY

JOHN WILEY & SONS LTD

Año: 2009 vol. 23 p. 707 - 713

0269-3879

ABSTRACT: Individualization of topotecan dosing reduces inter-patient variability in topotecan exposure, presumably reducing toxicity and increasing efficacy. However, logistical limitations (e.g. requirement for plasma, intensive bedside plasma processing) have prevented widespread application of this approach to dosing topotecan. Thus, the objectives of the presentstudy were to develop and validate an HPLC with fluorescence detection method to measure topotecan lactone in whole blood samples and to evaluate its application to individualizing topotecan dosing. Plasma samples (200 mL) were prepared using methanolic precipitation, a filtration step and then injection of 100 mL of the methanolic extract onto a Novapak® C18,4 mm, 3.9 × 150mm column with an isocratic mobile phase. Analytes were detected with a Shimadzu Fluorescence RF-10AXL detector with an excitation and emission wavelength of 370 and 520 nm, respectively. This method had a lower limit of quantification of 1 ng/mL (S/N ≥ 5; RSD 4.9%) and was validated over a linear range of 1–100 ng/mL. Results from a 5-dayvalidation study demonstrated good within-day and between-day precision and accuracy. Data are presented to demonstrate that the present method can be used with whole blood samples to individualize topotecan dosing in children with cancer.