Guanfacine-13C,15N3 is intended for us as an internal standard for the quantification of guanfacine (Item No. 22907) by GC- or LC-MS. Guanfacine is an a2-adrenergic receptor (a2-AR) agonist with Ki values of 93, 1,380, and 3,890 nM for a2A-, a2B-, and a2C-ARs, respectively, in a radioligand binding...