Relative bioavailability of a paracetamol suppository

Area of Science:

• Pharmacology
• Drug Delivery Systems

Background:

• Paracetamol (acetaminophen) is a widely used analgesic and antipyretic.
• Suppositories offer an alternative route of administration for medications.

Purpose of the Study:

• To compare the relative bioavailability of a new paracetamol suppository formulation (Panodil) against oral tablets.
• To evaluate the pharmacokinetic profiles of paracetamol following rectal and oral administration.

Main Methods:

• A pharmacokinetic study was conducted in eight healthy adult subjects.
• Subjects received paracetamol via suppository and tablet formulations at 0.5 g and 1 g doses.
• Plasma paracetamol concentrations were measured over time to determine bioavailability and absorption rates.

Main Results:

• Oral tablets demonstrated faster absorption and achieved higher peak plasma concentrations than suppositories.
• The relative bioavailability of paracetamol suppositories was approximately 80% compared to the tablet formulations.
• No evidence of dose-dependent (capacity-limited) elimination was observed for paracetamol at the tested doses.

Conclusions:

• Paracetamol suppositories provide a viable alternative, though with lower and slower bioavailability than oral tablets.
• The 80% bioavailability suggests rectal administration may be suitable when oral intake is not feasible.
• Further studies could explore factors influencing suppository absorption and patient-specific responses.