Alfentanil Hydrochloride

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Cat Number

API69049065

CAS Number

69049-06-5

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Product Detail Description Scientific Support Customer Q&A

CAS Number

69049-06-5

Storage

Under -20°C

Synonyms

Alfentanil HCl

Molecular Formula

C21H33ClN6O3

Molecular Weight

453

Smiles

CCC(=O)N(C1=CC=CC=C1)C2(CCN(CC2)CCN3C(=O)N(N=N3)CC)COC.Cl

Appearance

Solid

General Description

Alfentanil Hydrochloride is the hydrochloride salt of alfentanil, a synthetic opioid analgesic of the 4-anilidopiperidine class. It is a structural analog of fentanyl but with a unique thiazolidinedione substituent, resulting in a considerably shorter onset and duration of action due to its lower lipophilicity and higher plasma protein binding at physiological pH.

Mechanism of Action

Alfentanil Hydrochloride acts as a full agonist at mu-opioid receptors (MOR) in the central nervous system and peripheral tissues, activating Gi/o-coupled signaling pathways that reduce neuronal excitability, decrease cAMP production, and modulate potassium and calcium ion channel conductance.

Application

Used as a short-acting opioid analgesic for induction and maintenance of anesthesia and for short surgical procedures. Alfentanil Hydrochloride is a 4-anilidopiperidine opioid with rapid onset and short duration of action due to its low lipophilicity and favorable pharmacokinetic profile.

Alfentanil hydrochloride acts as a potent μ-opioid receptor agonist. An in vitro study using AtT20 cells expressing μ-opioid receptors and membrane potential dye assays demonstrated that alfentanil, together with morphine and fentanyl, exhibits rapid dissociation kinetics from the μ-opioid receptor. This rapid dissociation was measured by the rate at which the agonist effect reversed following washout. In contrast, other synthetic opioids such as carfentanil and isotonitazene displayed markedly slower dissociation rates. The rapid dissociation of alfentanil from the receptor correlates directly with higher sensitivity to antagonism by naloxone, the standard opioid overdose reversal agent. Agonists with slow dissociation kinetics were found to be more resistant to naloxone reversal, requiring higher doses for effective antagonism.

Fig. 1 Concentration–response of Alfentanil reversing opioid-induced hyperpolarization in μ-opioid receptor-expressing AtT20 cells. (Alhosan N.; et al. 2025)

References

Alhosan N, et al. Slow dissociation kinetics of fentanyls and nitazenes correlates with reduced sensitivity to naloxone reversal at the μ‐opioid receptor. British journal of pharmacology, 2025, 182(4): 969-987.

How does Alfentanil Hydrochloride differ from fentanyl in clinical pharmacokinetics?

Alfentanil Hydrochloride has a significantly shorter context-sensitive half-time and faster equilibration between plasma and brain compared to fentanyl, resulting from its lower pKa and higher non-ionized fraction at physiological pH.

What storage conditions are required?

Must be stored under -20℃ in a tightly sealed container, protected from light and moisture.

What purity grade is available?

Supplied as a high-purity grade suitable for R&D and pharmaceutical manufacturing.

Can packaging be customized?

Order quantities and packaging formats can be customized to meet specific R&D and production requirements.