Bioavailability of Two Sublingual Formulations of Ketorolac Tromethamine 30 mg: A Randomized, Open-Label, Single-Dose, Two-Period Crossover Comparison in Healthy Mexican Adult Volunteers

Background: Ketorolac tromethamine (ie, ketorolac) is an NSAID that appears to have several mechanisms of action, including inhibition of prostaglandin synthesis, modulatory effect on opioid receptors, and nitric oxide synthesis. Ketorolac is used in the treatment of pain. There are various generic formulations of sublingual ketorolac available in Mexico. However, a literature search did not identify published data concerning the bioavailability of these formulations in the Mexican population. Objective: The aim of this study was to compare the bioavailability of 2 sublingual formulations of ketorolac 30-mg tablets in healthy Mexican adult volunteers. Methods: This was a randomized-sequence, open-label, single-dose, 2-period crossover (2 dosing periods x 2 treatments) study comparing the bioavailability of two 30-mg sublingual tablet formulations of ketorolac. Healthy Mexican adult (aged, 18-55 years) men and women were eligible for inclusion. Subjects were randomly assigned in a 1:1 ratio to receive a single dose of the test formulation or the reference formulation. After a 12-hour overnight fast, subjects received a single dose of the corresponding formulation. There was a 7-day washout period between administration periods. Plasma samples were obtained over a 24-hour period after administration. Plasma ketorolac concentrations were analyzed by high-performance liquid chromatography for analysis of pharmacokinetic properties, including C-max AUC(0-24), and AUC(0-infinity). Blood samples were drawn immediately after sublingual placement of the drug and at 10, 20, 30, 40, 50, 60, 75, and 90 minutes and 2, 4, 6, 8, 10, 12, and 24 hours after dosing. The formulations were considered bioequivalent if the geometric mean ratios of Cm, and AUC were within the predetermined range of 80% to 125% and if P for the 90% CIs was <0.05. Tolerability was assessed by vital sign monitoring, laboratory analysis results, and subject interviews. Results: A total of 27 subjects (18 women, 9 men; mean [SD] age, 27 [9] years [range, 18-47 years]; weight, 61 [8] kg [48-79 kg]; height, 163 [8] cm [150180 cm]) were enrolled and completed the study. Fourteen subjects received the test formulation first. No period or sequence effect was observed. The 90% CIs for the corresponding differences in natural log C-max,AUC(0-24), and AUC(0-infinity) were 95.94% to 114.66%, 98.34% to 105.90%, and 99.25% to 108.36%, respectively (all, P < 0.05), meeting the predetermined criteria for bioequivalence. Sixteen subjects experienced a total of 20 adverse events (AEs) during the study. None of the AEs were considered serious. One AE (nausea) appeared to be related to use of the reference formulation. Conclusions: In this small study in 27 healthy Mexican adult volunteers, the test formulation of a single, 30-mg sublingual tablet of ketorolac appeared to be bioequivalent to the reference formulation based on the rate and extent of absorption. Both formulations were well tolerated. (Clin Ther. 2008;30:16671674) (C) 2008 Excerpta Medica Inc.