Validated high-performance liquid chromatographic methods for quantitation of a novel nonsteroidal antiestrogen

HPLC assays were developed and validated for the quantitation of the novel orally active nonsteroidal antiestrogen EM-800 ¿(S)-(+)-4-[7-(2,2-dimethyl-l-oxopropoxy)-4-methyl-2-[4-[2-(1-pipe ridinyl)- ethoxy]phenyl]-2H-l-benzopyran-3-yl]-phenyl 2,2-dimethylpropanoate¿. The assay involves reversed-phase C18 or C4 columns using different mobile phases with ammonium acetate buffers and UV detection at lambda = 240 nm. The standard curve was linear over the concentration range of 10-1100 micrograms/ml. The precision (% relative standard deviation) values of these methods were in the range of 0.38-0.52 and 1.89-3.45% with C4 and C18 reversed phases, respectively. The limit of detection was found to be 1 microgram/ml. Enantiomeric separation was also obtained using a chiral method (ChiralPak AD column) using a mixture of hexane-reagent alcohol-diethylamine (94.9:5.0:0.1) as mobile phase. These methods were applied to stability studies, evaluation of pharmaceutical dosage forms and in the framework of toxicological studies. Details of some of these applications will be presented.