Furosemide-d₅is intended for use as an internal standard for the quantification of furosemide by GC- or LC-MS. Furosemide is a loop diuretic and an inhibitor of the Na⁺/K⁺/2Cl^-(NKCC) cotransporters, NKCC1 and NKCC2 (K_is =^~10 µM for both).^1,2In vivo, furosemide (0.1 mg/kg, p.o.) increases diuresis in beagle dogs.³Furosemide (30 mg/kg) reduces ventricular collagen deposition and fibrosis in a rat model of dilated cardiomyopathy.⁴It is also an inhibitor of carbonic anhydrase I (CAI), CAII, and CAIII (K_is = 0.052-0.065 µM) and organic ion transporter 1 (OAT1; K_i= 9.5 µM), as well as a GABA_Areceptor antagonist.^5,6,7

1.Gillen, C.M., Brill, S., Payne, J.A., et al.Molecular cloning and functional expression of the K-Cl cotransporter from rabbit, rat, and human. A new member of the cation-chloride cotransporter familyJ. Biol. Chem.271(27)16237-16244(1996) 2.Markadieu, N., and Delpire, E.Physiology and pathophysiology of SLC12A1/2 transportersPflugers Arch.466(1)91-105(2014) 3.Potter, B.M., Ames, M.K., Hess, A., et al.Comparison between the effects of torsemide and furosemide on the reninangiotensin-aldosterone system of normal dogsJ. Vet. Cardiol.2651-62(2019) 4.Watanabe, K., Sreedhar, R., Thandavarayan, R.A., et al.Comparative effects of torasemide and furosemide on gap junction proteins and cardiac fibrosis in a rat model of dilated cardiomyopathyBiofactors43(2)187-194(2017) 5.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) 6.Rajan, S.T., Kumar, M.K., and Ramakrishna, M.The novel process for the preparation of (1R,2R,3aS,9aS)-[[2,3,3a,4,9,9a-hexahydro-2-hydroxy-1-[(3S)-3-hydroxyoctyl]-1H-benz[f]inden-5-yl]-oxy]acetic acid(2014) 7.Siess, W., Siegel, F.L., and Lapetina, E.G.Dihomogammalinolenic acid, but not eicosapentaenoic acid, activates washed human plateletsBiochim. Biophys. Acta.801(2)265-276(1984)