Influence of Ginkgo biloba extract on the pharmacodynamic effects and pharmacokinetic properties of ticlopidine: an open-label, randomized, two-period, two-treatment, two-sequence, single-dose crossover study in healthy Korean male volunteers.

BACKGROUND: Ginkgo biloba extract is an herbal medicine used in the treatment of vascular disorders that may be coadministered with antiplatelet agents such as ticlopidine. Regulatory authorities requested evaluation of the pharmacodynamic and pharmacokinetic interactions between these entities, according to the drug-development guidance for fixed-dose combination formulations in Korea. OBJECTIVE: This study was performed to evaluate the potential pharmacodynamic and pharmacokinetic interactions between ticlopidine and Ginkgo biloba extract. METHODS: An open-label, randomized, 2-period, 2-treatment, 2-sequence, single-dose crossover study was conducted in healthy Korean male volunteers. All volunteers were randomly assigned to a sequence group for the 2 treatments, which consisted of ticlopidine 250 mg alone and ticlopidine 250 mg with Ginkgo biloba extract 80 mg, separated by a 1-week washout period between the treatments. Bleeding time was determined just before dosing and at 5, 12, and 48 hours after dosing. Platelet aggregation was evaluated before dosing and at 4, 8, 26, and 48 hours after dosing. Blood samples (8 mL) from each of the volunteers were collected from an indwelling intravenous cannula inserted into a forearm vein before dosing and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 24, and 48 hours after dosing. Ticlopidine concentrations were determined by a validated method using HPLC and ultraviolet detection. Adverse events were identified using general health-related questions, vital signs, physical examinations, ECGs, and laboratory tests. RESULTS: A total of 24 healthy men participated in the study (mean [SD] age, 24.1 [4.3] years; weight, 66.6 [7.4] kg; height, 174.7 [5.0] cm). The baseline corrected bleeding times were not significantly different between the ticlopidine-alone and ticlopidine/ Ginkgo biloba groups, and changes in platelet aggregation were not significantly different between the groups. Likewise, the pharmacokinetic parameters of ticlopidine were not significantly different between the groups; the geometric mean ratios of the ticlopidine/ Ginkgo biloba group to the ticlopidine-alone group were 1.03 (90% CI, 0.92-1.16) for C(max), 1.08 (90% CI, 0.98-1.19) for AUC(0-last), and 1.10 (90% CI, 1.00-1.20) for AUC(0-infinity). A total of 28 adverse events were reported: 11 in the ticlopidine-alone group and 17 in the ticlopidine/Ginkgo biloba group. The adverse events judged to be possibly related to ticlopidine in the ticlopidine-alone group were epigastric discomfort (2 cases), diarrhea (1), skin eruption (1), and a feeling of being cold (1) or hot (1). The adverse events judged to be related to ticlopidine or Ginkgo biloba in the ticlopidine/Ginkgo biloba group were epigastric discomfort (2), diarrhea (2), nausea (2), and headache (1). CONCLUSIONS: In this small group of healthy Korean men, the addition of a single dose of Ginkgo biloba extract did not prolong the bleeding time and was not associated with additional antiplatelet effects compared with the administration of ticlopidine alone. The coadministration of Ginkgo biloba extract with ticlopidine was not associated with any significant changes in the pharmacokinetic profile of ticlopidine compared with ticlopidine administered alone.

Comparison of the pharmacokinetics of ticlopidine between administration of a combined fixed-dose tablet formulation of ticlopidine 250 mg/ginkgo extract 80 mg, and concomitant administration of ticlopidine 250-mg and ginkgo extract 80-mg tablets: an open-label, two-treatment, single-dose, randomized-sequence crossover study in healthy Korean male volunteers.

BACKGROUND: Ticlopidine is an antiplatelet agent used for the prevention of vascular accidents. In clinical practice in Korea, ginkgo extract may be administered along with ticlopidine to enhance the inhibition of platelet aggregation. OBJECTIVE: To meet the requirements for marketing a combined fixed-dose formulation in Korea, the investigators compared the pharmacokinetic characteristics of ticlopidine in a combined fixed-dose tablet of ticlopidine/ginkgo extract with the concomitant administration of ticlopidine and ginkgo extract tablets. METHODS: An open-label, 2-period, 2-treatment, single-dose, randomized-sequence crossover study was conducted in healthy Korean male volunteers. Subjects were randomly allocated to 2 sequence groups. In one period, a combined ticlopidine 250 mg/ ginkgo extract 80-mg fixed-dose tablet was administered and, in the other period, ticlopidine 250-mg and ginkgo extract 80-mg tablets were concomitantly administered. A 7-day washout separated the 2 periods. For analysis of pharmacokinetic properties, including C(max), T(max), t((1/2)), AUC(0-infinity), and AUC(0-last), serial blood sampling was performed up to 48 hours after study drug administration during each period. Ticlopidine concentrations in plasma were determined by a validated method using LC-MS/MS. In order for the 2 treatments to be considered bioequivalent, the 90% CI of the geometric means ratios for C(max) and AUC needed to be between 80% and 125%. Bleeding time was determined before dosing (0 hour) and at 5 and 24 hours after dosing. Adverse events (AEs) were identified through patient interview, recording of blood pressure, heart rate, and body temperature, physical examination, 12-lead ECG, and laboratory assessments. RESULTS: Twenty-four healthy Korean male subjects (mean [range] age, 23.9 [22-38] years; height, 174.0 [162-184] cm; weight, 67.4 [56-80] kg) completed the study. Median (range) T(max) of ticlopidine was 1.5 (0.5-2.0) hours in both groups. The mean (SD) t((1/2)) of ticlopidine in the combined fixed-dose formulation and the concomitant administration groups was 19.5 (3.4) and 19.0 (3.3) hours after study drug administration, respectively. The geometric means ratios of ticlopidine AUC(0-last), AUC(0-infinity), and C(max) between the combined fixed-dose formulation and concomitant administration were 1.04 (90% CI, 0.96-1.13), 1.04 (90% CI, 0.96-1.13), and 1.09 (90% CI, 0.96-1.23), respectively. The mean (SD) bleeding time at predose (0), and 5 and 24 hours after dose administration was 4.5 (1.6) to 5.4 (1.7) minutes in the combined fixed-dose formulation group and 4.4 (1.6) to 5.1 (1.1) minutes in the concomitant administration group. Five subjects (3 in the combined fixed-dose formulation group and 2 in the concomitant administration group) had bleeding times >8 minutes, but this was not considered to be clinically significant. A total of 24 AEs were reported in 13 of 24 subjects: nausea (3 cases), diarrhea (3), dizziness (3), epigastric discomfort (2), headache (2), rhinorrhea (2), purulent sputum (2), dyspepsia (1), upper abdominal pain (1), cough (1), pharyngolaryngeal pain (1), oropharyngeal swelling (1), dysphonia (1), and dysphagia (1). All were considered mild or moderate in nature. There was no statistically significant difference between the 2 treatments in the number of AEs or in the number of subjects who reported an AE. CONCLUSION: Administration of a single dose of a combined fixed-dose formulation of ticlopidine 250 mg/ ginkgo extract 80-mg tablets and concomitant administration of ticlopidine and ginkgo extract tablets did not result in statistically significant differences in the pharmacokinetics of ticlopidine in these healthy Korean male volunteers.