Roflumilast-d4 is intended for use as an internal standard for the quantification of roflumilast by GC- or LC-MS. Roflumilast is a potent, cell-permeable inhibitor of PDE4 (IC50 = <1 nM for both human PDE4B and PDE4D).1 It is selective for PDE4, with IC50 values against other PDE forms being greater than 10 μM.
1.Card, G.L., England, B.P., Suzuki, Y., et al.Structural basis for the activity of drugs that inhibit phosphodiesterasesStructure12(12)2233-2247(2004)