A Gradient HPLC Test Procedure for the Determination of Impurities and the Synthetic Precursors in 2-[4-(1-Hydroxy-4-[4-(Hydroxydiphenylmethyl)-1-Piperidinyl]-butyl)-Phenyl]-2-Methylpropionic Acid

A gradient high-performance liquid chromatographic (HPLC) test procedure is developed and evaluated for its ability to establish the levels of impurities and remaining synthetic precursors in 2-[4-(1-hydroxy-4-[4-(hydroxydiphenylmethyl)-1-piperidinyl]-butyl)-phenyl]-2-methylpropionic acid. A gradient program with a mobile phase of 0.02M sodium phosphate buffer and 0.004M sodium perchlorate in acetonitrile water (∼ pH 2.5) is used with a Spherisorb C6 column. The acetonitrile composition is increased linearly from 40% to 65% over a 45-min period and held at 65% for 20 min. UV detection at 210 nm is used to quantitate all components. The procedure is validated for accuracy using spiked levels (0.1% to 1.5%, w/w) with two suspected impurities, the synthetic precursors. A multiday repeatability study using two different Spherisorb C6 columns and HPLC systems shows consistent impurity quantitation results with one production lot of the bulk compound.