Determination of (4‐(1, 3‐dioxo‐1, 3‐dihydro‐2H‐isoindol‐ 2‐yl)‐N′‐[(4‐ethoxyphenyl) methylidene] benzohydrazide, a novel anti‐inflammatory agent, in biological fluids by UPLC‐MS/MS: Assay development, validation and in vitro metabolic stability study. (7th May 2017)