Bioavailability and Bioequivalence of Two Oral Single Dose of Ibuprofen 400 mg to Healthy Volunteers Saied M. I. Al-Dalaen, Abdul-Wahab R. Hamad, Tayel A. AL-Hujran, Hayat A. Al-Btoush, Lidia Al-Halaseh, Mousa K. Magharbeh, Nariman A. Al-Jawabri, Islam A. Al-Kasasbeh and Fadhil M. Abid. Biomedical and Pharmacology Journal; 2021: 14 (1), pp. 435-444. The objective of the two pharmacokinetic studies reported here was to compare the relative bioavailability and bioequivalence of an ibuprofen 400 mg tablet from National Company (SDI) as a test with a reference formulation. Evaluation of two open, randomized, cross-over studies, one single dose in healthy male volunteers. 20 healthy volunteers were randomized in a cross-over design to single dose of Profedin 400 mg produced from National Company, ibuprofen formulation, as a test and a reference formulation produced from Pharmacia & Upjohn, Ibuprofen 400 mg. Ibuprofen and standard of ibuprofen were analyzed by utilizing HPLC, the sample extracted from 0.5ml of plasma with an organic solution of isooctane and 2-propanol. The mobile phase consisted of 44% acetonitrile and 0.1% phosphoric acid. The flow rate was 1 ml/min. The analytical column was a C-18, 5um packing size. Detection of Ibuprofen and the internal standard occurred by UV absorbance at wavelength of 220nm. A single-dose study demonstrated that the bioavailability of ibuprofen for both formulations was not significantly different. In addition, mean plasma levels of ibuprofen predictive of clinical efficacy were achieved within 1.5- 2.0 hours and the elimination of ibuprofen tablets is virtually complete in 12 hours after the single dose. The serum half-life is 1.8 to 2.0 hours. The Cmax, Tmax, Kelemin.0.5 were calculated for the test and reference. They were not significantly different. Blood levels predicted that the present slow-release formulation of ibuprofen should offer reliable day and night control of pain and fever and is associated with a favorable safety profile.