Notes: (±)-4-hydroxy Propranolol β-D-glucuronide is a metabolite of the β-adrenergic receptor antagonist 4-hydroxy propranolol (Item No. 18630).{51237} It is formed from propranolol (Item No. 23349) via a 4-hydroxy propranolol intermediate by the UDP-glucuronosyltransferase (UGT) isoforms UGT1A9 and UGT2A1.