Chemical Name of Fentanyl
The chemical name of fentanyl is N-Phenyl-N-(1-(2-phenylethyl)-4-piperidinyl) propanamide. 1
Molecular Structure and Properties
The molecular formula is C₂₂H₂₈N₂O with a molecular weight of 336.5 1
Fentanyl has an n-octanol:water partition coefficient of 860:1, reflecting its high lipid solubility 1
The pKa is 8.4 1
Chemical Classification
Fentanyl belongs to the phenylpiperidine class of synthetic opioids, characterized by a phenyl moiety directly attached to a piperidine ring 2
It is also referred to as N-(1-phenethylpiperidin-4-yl)-N-phenylpropionamide in chemical nomenclature 3
As a second-generation synthetic phenylpiperidine series opioid, fentanyl was introduced into clinical anesthesia practice as fentanyl citrate in 1968 2
Clinical Relevance of Chemical Properties
The high lipophilicity (reflected in the 860:1 partition coefficient) enables fentanyl to rapidly cross the blood-brain barrier and allows for multiple routes of administration including transdermal, transmucosal, buccal, intranasal, and parenteral delivery 4, 1
The low molecular weight (336.5) combined with high potency makes fentanyl suitable for transdermal therapeutic systems 1, 5
High first-pass metabolism makes oral formulations unfeasible, but the lipophilicity allows absorption via non-oral routes 6