HPLC Determination of Letrozole in Plasma Using Fluorescence Detection: Application to Pharmacokinetic Studies

Abstract

A simple, rapid and sensitive HPLC method has been developed and validated for the analysis of letrozole in human plasma. The separation was achieved on a monolithic silica column using acetonitrile–phosphate buffer. A fluorescence detector was used for the quantitation with excitation and emission wavelengths at 230 and 295 nm. The assay enables the measurement of letrozole for therapeutic drug monitoring with a minimum quantification limit (LOQ) of 0.5 ng mL−1. The method involves a simple, one-step extraction procedure with complete recovery. Calibration was linear over the concentration range 0.5–80 ng mL−1. The coefficients of variation for inter-day and intra-day assay were found to be less than 8%.