Author(s): Varad R. Pradhan, Rathnam M.V
Bicalutamide (BCT) is a non-steroidal antiandrogen and is an oral medication that is used for the treatment of prostate cancer. Its chemical name is (RS)-N-[4-cyano-3-(trifluoromethyl) phenyl]-3-[(4-fluorophenyl) sulfonyl]-2-hydroxy-2-methyl-propanamide. BCT as such is a racemic mixture, but most of its pharmacological activity is attributed to its R enantiomer. A single, simple and selective method for the estimation of R enantiomer of BCT in human plasma was validated using external standard method. The drug was separated from its S enantiomer on Ultron ES OVM chiral column under isocratic conditions consisting of 12.5mM ammonium formate buffer and ethanol (75:25, v/v), with a total run time of 15 minutes and detected by tandem mass spectrometry with negative ionization mode. Complete baseline separation between both the enantiomers was obtained with excellent precision and accuracy for R BCT, thus supporting stereo specific pharmacokinetic studies of the active enantiomer. Linearity in plasma was observed over the concentration range 10.020 – 601.200 ng/mL. Stability was evaluated under different conditions including bench top, processed sample, freeze and thaw, autosampler and long term.