Sensitive and rapid high‐performance liquid chromatography tandem mass spectrometry method for estimation of fulvestrant in rabbit plasma

A rapid and sensitive high-performance liquid chromatography and electrospray tandem mass spectrometry method was developed and validated for estimation of fulvestrant in rabbit plasma using liquid-liquid extraction. The separation and quantification of fulvestrant were achieved by reverse-phase chromatography on a Sunfire C18 column (50 x 2.1. i.d., 3.5 microm) with isocratic elution at a flow rate of 300 microL/min using norethistrone as an internal standard from 500 microL plasma sample. The method was validated over the concentration range from 0.092 to 16.937 ng/mL with a lower limit of detection of 0.023 ng/mL. The intra-day and inter-day accuracy and precision were within 10%. The recovery was 85 and 90% for fulvestrant and norethistrone respectively. The chromatographic run time was only 2.5 min.