Characterization of tepoxalin and its related compounds by high-performance liquid chromatography/mass spectrometry

High-performance liquid chromatography/mass spectrometry (HPLC/MS) was used to identify and elucidate key structural characteristics of a novel dual cyclooxygenase/lipoxygenase inhibitor, tepoxalin (3-[5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-pyrazolyl]-N-hydroxy- N-methylpropanamide), its synthesis-related byproducts in bulk drug substance, and degradation products stemming from probe stability studies. Such information is needed to assist in synthesis optimization and in the preparation of stable formulations for toxicity studies and clinical trials. High-performance liquid chromatography, in conjunction with mass spectrometry (HPLC/MS) and UV photodiode array detection, can often expedite the gathering of preliminary data that contribute to several aspects of the pharmaceutical development process.