11 DESCRIPTION The system contains fentanyl, an opioid agonist, for transdermal administration. The amount of fentanyl released from each system per hour is proportional to the surface area (25 mcg/hour per 9.44 cm 2 ). The composition per unit area of all transdermal system sizes is identical. * Nominal delivery rate is 12.5 mcg/hour per hour ** Nominal delivery rate per hour Strength (mcg/hour) Size (cm²) Fentanyl Content (mg) 12* 4.72 1.33 25** 9.44 2.66 50** 18.88 5.32 75** 28.32 7.99 100** 37.76 10.65 The molecular weight of fentanyl base is 336.5, and the molecular formula is C 22 H 28 N 2 O. The n-octanol: water partition coefficient is 860:1. The pKa is 8.4. The chemical name is N-Phenyl-N-(1-(2-phenylethyl)-4-piperidinyl) propanamide. The structural formula is: Fentanyl transdermal system is a rectangular translucent system with rounded corners. The product name, “FENTANYL” and dosage strength are printed in green on each system. Each system is comprised of a clear polyethylene terephthalate (PET) release liner and two functional layers. Proceeding from the outer surface toward the surface adhering to skin, these functional layers are: 1) a translucent backing layer of ethylene vinyl acetate/polyethylene terephthalate (EVA/PET) film with green print; 2) a drug-in-adhesive layer containing fentanyl, acrylate copolymer adhesive, and methyl laurate. Before use, a clear PET release liner covering the drug-in-adhesive layer is removed and discarded. Structural Formula Parts of the Fentanyl Transdermal System Patch
⚠️ Warnings
Waste material should be disposed of safely. Patients/carers should be encouraged to return any unused product to the Pharmacy, where it should be disposed of in accordance with national and local requirements.
