Bufuralol-d9 is intended for use as an internal standard for the quantification of bufuralol by GC- or LC-MS. Bufuralol is a non-selective antagonist of β-adrenergic receptors (β-ARs) that also has partial agonist activity.1,2,3 It decreases mean arterial blood pressure and increases abdominal aortic blood flow in anesthetized cats when administered intravenously at doses of 0.3 and 1 mg/kg.3 Bufuralol is hydroxylated at the 1' position by the cytochrome P450 (CYP) isoform CYP2D6 and has been used as a substrate to measure CYP2D6 activity.4,1,5,6

|1. Narimatsu, S., Takemi, C., Kuramoto, S., et al. Stereoselectivity in the oxidation of bufuralol, a chiral substrate, by human cytochrome P450s. Chirality 15(4), 333-339 (2003).|2. Pringle, T.H., Francis, R.J., East, P.B., et al. Pharmacodynamic and pharmacokinetic studies on bufuralol in man. Br. J. Clin. Pharmac. 22(5), 527-534 (1986).|3. Blaber, L.C., Burden, D.T., Eigenmann, R., et al. The effects of bufuralol, a β-adrenoceptor antagonist with predominant β2-adrenoceptor agonistic activity, in the cat and the dog. J. Cardiovasc. Pharmacol. 6(1), 165-175 (1984).|4. Yamazaki, H., Guo, Z., Persmark, M., et al. Bufuralol hydroxylation by cytochrome P450 2D6 and 1A2 enzymes in human liver microsomes. Mol. Pharmacol. 46(3), 568-577 (1994).|5. Paine, M.J.I., Gilham, D., Roberts, G.C.K., et al. Functional high level expression of cytochrome P450 CYP2D6 using baculoviral expression systems. Arch. Biochem. Biophys. 328(1), 143-150 (1996).|6. Chen, N., Cui, D., Wang, Q., et al. In vitro drug-drug interactions of budesonide: Inhibition and induction of transporters and cytochrome P450 enzymes. Xenobiotica 48(6), 637-646 (2018).