We have developed a sensitive HPLC assay to quantitate the active lactone form of 9-aminocamptothecin (9AC) in human plasma over the concentration range 10-0.25 nM (0.091 ng/ml). Solid-phase extraction separated 9AC lactone from its less active metabolite, 9AC carboxylate, allowing samples to be stored for up to two months prior to reversed-phase HPLC analysis. An acidic (pH 2.55) isocratic HPLC mobile phase was used to enhance 9AC fluorescence resulting in an over 50-fold increase in assay sensitivity compared to previous methods. This assay was able to measure steady-state 9AC lactone concentrations even at the lowest dose level of 9AC used in our Phase I clinical trial.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Chromatography B: Biomedical Sciences and Applications|
|State||Published - Apr 22 1994|
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