Absolute and relative bioavailability of oral acetaminophen preparations

Barbara Ameer, Marcia Divoll, Darrell R. Abernethy, David J. Greenblatt, Leon Shargel

Research output: Contribution to journalArticlepeer-review


Eighteen healthy volunteers received single 650‐mg doses of acetaminophen by 5‐min intravenous infusion, in tablet form by mouth in the fasting state, and in elixir form orally in the fasting state in a three‐way crossover study. An additional eight subjects received two 325‐mg tablets from two commercial vendors in a randomized crossover fashion. Concentrations of acetaminophen in multiple plasma samples collected during the 12‐hr period after each dose were determined by high‐performance liquid chromatography. Following a lag time averaging 3–4 min, absorption of oral acetaminophen was first order, with apparent absorption half‐life values averaging 8.4 (elixir) and 11.4 (tablet) min. The mean time‐to‐peak concentration was significantly longer after tablet (0.75 hr) than after elixir (0.48 hr) administration. Peak plasma concentrations and elimination half‐lives were similar following both preparations. Absolute systemic availability of the elixir (87%) was significantly greater than for the tablets (79%). Two commercially available tablet formulations did not differ significantly in peak plasma concentrations, time‐to‐peak, or total area under the plasma concentration curve and therefore were judged to be bioequivalent.

Original languageEnglish (US)
Pages (from-to)955-958
Number of pages4
JournalJournal of Pharmaceutical Sciences
Issue number8
StatePublished - Aug 1983


  • Acetaminophen—absolute and relative bioavailability of oral preparations, determination by high‐performance liquid chromatography
  • Bioavailability—absolute and relative, oral acetaminophen preparations, determined by high‐performance liquid chromatography
  • High‐performance liquid chromatography—oral acetaminophen preparations, determination of absolute and relative bioavailability

ASJC Scopus subject areas

  • Pharmaceutical Science

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