Cetirizine-d8 (hydrochloride) is intended for use as an internal standard for the quantification of cetirizine , (R)-cetirizine , and (S)-cetirizine by GC- or LC-MS. Cetirizine is a bioactive carboxylated metabolite of hydroxyzine that acts as a selective histamine H1 receptor antagonist (Ki = 10 nM).1,2 As a second generation antihistamine, it is non-sedating due to low lipophilicity, which prevents blood-brain barrier transit.3 Cetirizine is a racemic mixture composed of equal amounts of two enantiomers, (R)-cetirizine and (S)-cetirizine, with pharmacological activity residing primarily in the (R) isomer.2 Cetirizine inhibits eosinophil chemotaxis and leukotriene B4 release independent from H1 antagonism.4 It inhibits aerosol histamine-induced bronchospasm in guinea pigs (ED50 = 100 μg/kg, p.o.).5 Formulations containing cetirizine have been used in the treatment of allergic rhinitis and chronic urticaria.
1.Thurmond, R.L., Gelfand, E.W., and Dunford, P.J.The role of histamine H1 and H4 receptors in allergic inflammation: The search for new antihistaminesNat. Rev. Drug Discov.7(1)41-53(2008) 2.Zhang, L., Cheng, L., and Hong, J.The clinical use of cetirizine in the treatment of allergic rhinitisPharmacology92(1-2)14-25(2013) 3.Tillement, J.P.The advantages for an H1 antihistamine of a low volume of distributionAllergy55(suppl 60)17-21(2000) 4.K?ller, M., Hilger, R.A., Rihoux, J.P., et al.Cetirizine exerts anti-inflammatory effects on human neutrophilsInt. Arch. Allergy. Immunol.110(1)52-56(1996) 5.Llupià, J., Gras, J., and Llenas, J.Comparative antiallergic effects of second-generation H1-antihistamines ebastine, cetirizine and loratadine in preclinical modelsArzneimittelforschung53(2)93-97(2003)