USE OF A RAPID HPLC ASSAY FOR DETERMINATION OF PHARMACOKINETIC PARAMETERS OF IBUPROFEN IN PATIENTS WITH CYSTIC-FIBROSIS

High doses of ibuprofen have been shown to delay the progression of lu ng disease without serious adverse effects in patients with cystic fib rosis. To be effective, peak ibuprofen concentration of 50 to 100 mg/L has to be achieved. We developed an HPLC assay to rapidly determine p lasma ibuprofen concentration. We used this assay to determine the pha rmacokinetics of ibuprofen in patients with cystic fibrosis. The assay possessed Linearity up to 500 mg/L, sensitivity to 1 mg/L, average re covery of 98%, and run-to-run precision (n = 23) of 3%. Furthermore, t he assay proved to be free of interference from 51 medications. Observ ed time to peak concentration varied significantly between those recei ving ibuprofen tablets (mean + SD, 94 +/- 29 min, n = 16) and syrup (3 0 +/- 0 min, n = 4) (P <0.0001). We conclude that the method described here is ideal, for therapeutic monitoring of ibuprofen.