Metolazone-d₇is intended for use as an internal standard for the quantification of metolazone by GC- or LC-MS. Metolazone is a thiazide-like diuretic.^1,2It inhibits the Na⁺/Cl^-cotransporter (IC₅₀= 0.3 µM for the rat transporter) and human carbonic anhydrase VII (CAVII), CAXII, and CAXIII (K_is = 2.1, 5.4, and 15 nM, respectively). Metolazone (0.3 and 1 mg/kg) induces fluid loss and enhances captopril-induced decreases in blood pressure in spontaneously hypertensive rats.³Formulations containing metolazone have been used in the treatment of high blood pressure.

1.Moreno, E., CristÓbal, P.S., Rivera, M., et al.Affinity-defining domains in the Na-Cl cotransporter: A different location for C- and thiazide bindingJ. Biol. Chem.281(25)17266-17275(2006) 2.Temperini, C., Cecchi, A., Scozzafava, A., et al.Carbonic anhydrase inhibitors. Interaction of indapamide and related diuretics with 12 mammalian isozymes and X-ray crystallographic studies for the indapamide-isozyme II adductBioorg. Med. Chem. Lett.18(8)2567-2573(2008) 3.Chiu, P.J.S., Vemulapalli, S., and Barnett, A.Acute blood pressure and urinary responses to single dose combinations of captopril and diuretics in conscious spontaneously hypertensive ratsJ. Pharm. Pharmacol.37(2)105-109(1985)