Alfentanil Injection, USP contains alfentanil, an opioid agonist, chemically designated as N- [1- [2-(4-ethyl-4,5-dihydro-5-oxo-1H-tetrazol-1- yl) ethyl]-4-(methoxymethyl)-4-piperidinyl]-N-phenylpropanamide monohydrochloride (1:1) with a molecular weight of 452.98 and an n-octanol: water partition coefficient of 128:1 at pH 7.4. The structural formula of Alfentanil HCl is:
Alfentanil Injection, USP is a sterile, non-pyrogenic, preservative free aqueous solution containing alfentanil hydrochloride equivalent to 500 mcg per mL of alfentanil base for intravenous injection. The solution, which contains sodium chloride for isotonicity, has a pH range of 4.0 to 6.0. Each mL contains:
Active: Alfentanil base 500 mcg.
Inactive: Sodium Chloride 9 mg and Water for Injection q.s.