SUBSYS (fentanyl sublingual spray) is an opioid agonist, available as a sublingual spray designed to deliver doses of 100, 200, 400, 600, 800, 1200 and 1800 mcg of fentanyl. The chemical name of fentanyl is N-phenyl-N-[1-(2-phenylethyl)-4-piperidinyl]propanamide.
Fentanyl is a highly lipophilic compound (octanol-water partition coefficient at pH 7.4 is 860:1) that is freely soluble in ethanol and methanol and practically insoluble in water (1:40). The molecular weight of the free base is 336.47. The pKa is 8.4.
The inactive ingredients in SUBSYS include: dehydrated alcohol 63.6% (V/V), purified water, propylene glycol, xylitol, and L-menthol.