Pharma & Specialty Chemical Standards

Chlorpheniramine, a first-generation antihistamine, is chemically known as 8-Chloro-1-methyl-5H-dibenzo[a,d]cyclohepten-5-propamine (C16H17ClN, molecular weight 253.76 g/mol). It belongs to the ethylenediamine class, characterized by a dibenzocycloheptene ring system with a chloro substituent and a propylamine side chain. Therapeutically, it alleviates allergic symptoms by competitively inhibiting histamine at H1 receptors, reducing vasodilation and pruritus. It is a white, crystalline solid with moderate water solubility and high lipophilicity, facilitating blood-brain barrier permeability. Its mechanism involves antagonism of histamine-mediated G-protein coupled receptor signaling, modulating smooth muscle contraction and vascular permeability.