Pharmacokinetic Study Of Two Extended-Release Formulations Of Cilostazol In Healthy Korean Subjects: A Randomized, Open-Label, Multiple-Dose, Two-Period Crossover Study

Objectives: The aim of this study was to compare the pharmacokinetic characteristics and safety of two extended-release formulations of cilostazol after multiple oral doses in healthy Korean subjects. Materials and methods: A randomized, open-label, multiple-dose, two-period, crossover study was conducted in 30 healthy male subjects. In each treatment period, subjects received oral doses of 200 mg cilostazol SR (Pletaal SR Cap.) or cilostazol CR (Cilostan CR Tab.) once daily for 5 consecutive days, with a washout period of 9 days. Plasma concentrations of cilostazol and its metabolites were determined using a validated liquid chromatography-tandem mass spectrometry method. Results: 24 subjects completed the study. The maximum plasma concentrations (C-max,C-ss, geometric mean (geometric coefficient of variation, CV%)) of cilostazol after cilostazol SR and cilostazol CR regimens were 1,532.7 (43.2%) ng/mL and 548.3 (58.9%) ng/mL, respectively, and the areas under the plasma concentration-time curves within dosing intervals (AUC(tau), geometric mean (CV%)) were 17,060.7 (39.2%) hxng/mL and 7,485.7 (55.0%) hxng/mL, respectively. The geometric mean ratios (cilostazol SR/cilostazol CR) of the C-max,C-ss and AUC(tau) values were 2.7954 (90% confidence interval: 2.3561 - 3.3166) and 2.2791 (90% confidence interval: 1.9770 - 2.6273), respectively. Both cilostazol SR and cilostazol CR were well tolerated in all subjects, and no serious adverse events occurred. The total incidence of headache, which is the most common adverse drug reaction, was significantly higher with cilostazol SR (63.0%) than cilostazol CR (25.9%). Conclusion: Cilostazol SR showed significantly higher C-max,C-ss and AUC(tau) of cilostazol than cilostazol CR after 5 days of multiple dosing of extended-release formulations of cilostazol.