OBJECTIVE Recently a formulation of intravenous (IV) ibuprofen was developed in China for management of mild to moderate pain in patients who could not take oral medications or where intravenous administration was preferable. The aim of this study was to evaluate the pharmacokinetic properties and tolerability of single and multiple doses of ibuprofen injection in healthy Chinese volunteers. METHODS This open-label, single- and multiple-dose study was conducted in healthy Chinese volunteers. In the single-dose phase, subjects were randomized to receive a single dose of ibuprofen injection 0.2, 0.4, or 0.8 g administered as a 30-minute IV infusion with a 1-week washout between periods. Blood samples were collected at regular intervals from 0 to 12.5 hours after drug administration and were analyzed using a validated LC-MS/MS method. In the multiple-dose phase, subjects received 0.4 g ibuprofen every 6 hours for 9 doses. Blood samples were obtained before the 7th, 8th, and 9th administration to determine the Cmin at steady state; on the 9th intravenous administration, blood samples were also collected for 12.5 hours after drug administration. Pharmacokinetic parameters were estimated using a noncompartmental model. Tolerability was determined using clinical evaluation and monitoring of adverse events (AEs). RESULTS A total of 12 healthy male (n = 6) and female (n = 6) Chinese volunteers were enrolled and completed the trial. After IV administration of single dose, the mean (SD) Cmax value increased from 35.77 (6.98) to 117.12 (19.78) µg/mL, and the mean (SD) AUC0-t value increased from 67.63 (10.30) to 230.50 (33.55) µg×h/mL in the range of 0.2-g to 0.8-g dose. The terminal half-life in plasma was ~ 2.0 hours. After IV administration of 9 doses of ibuprofen 400 mg every 6 hours, the mean (SD) Cmax was 66.49 (8.49) µg/mL, the AUC0-t was 135.65 (26.91) µg×h/mL, the t1/2 was 2.14 (0.34) hours, the Cl/F was 3.34 (0.68) L/h, and the Vz/F was 10.32 (2.69) L, which were comparable with those after single dosing. The accumulation index was 1.17 (0.06), and the fluctuation was 304.0 (57.7) %. Results of the t-tests of Cmax and AUC found no significant differences between the male and female groups. No serious AEs were reported, and there were no discontinuations due to AEs. CONCLUSIONS The pharmacokinetics of ibuprofen exhibited dose-related kinetics from the 0.2- to the 0.8-g dose. After multiple doses, the pharmacokinetic parameters of ibuprofen were consistent with those after single doses. There was no accumulation in ibuprofen exposure in healthy Chinese between multiple doses and single dose. At the doses studied, ibuprofen appeared to be well tolerated in these healthy volunteers.
.