meta-Fexofenadine (meta-MDL-16455) is an impurity of Fexofenadine[1]. Fexofenadine, a H1R antagonist, is an anti-allergic agent used in seasonal allergic rhinitis and chronic idiopathic urticarial[2].
[1]. Maher HM, et al. Development of validated stability-indicating chromatographic method for the determination of fexofenadine hydrochloride and its related impurities in pharmaceutical tablets. Chem Cent J. 2011 Dec 3;5(1):76. [2]. Watanabe N, et al. The effects of fexofenadine on eosinophilia and systemic anaphylaxis in mice infected with Trichinella spiralis. Int Immunopharmacol. 2004 Mar;4(3):367-75.