Azelastine-d3 is the deuterium labeled Azelastine (HY-B0462A). Azelastine, an antihistamine, is a potent and selective histamine 1 (H1) antagonist. Azelastine can be used for the research of allergic rhinitis, asthma, diabetic hyperlipidemic and SARS-CoV-2[1][2][3][4].