Comparative Investigation of the Pharmacokinetics of Bosentan in Caucasian and Japanese Healthy Subjects

• Published in: Journal of clinical pharmacology Vol. 45; no. 1; pp. 42 - 47
• Main Authors: Giersbergen, Paul L. M., Dingemanse, Jasper
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.2005
• Subjects: Adult; Analysis of Variance; Area Under Curve; Asian Continental Ancestry Group; Bosentan; Caucasian and Japanese subjects; Confidence Intervals; Cross-Over Studies; Dose-Response Relationship, Drug; Double-Blind Method; endothelin receptor antagonist; European Continental Ancestry Group; Female; Humans; Male; Middle Aged; pharmacokinetics; Pyrimidines - metabolism; Sulfonamides - administration & dosage; Sulfonamides - blood; Sulfonamides - metabolism; Sulfonamides - pharmacokinetics
• ISSN: 0091-2700; 1552-4604
• DOI: 10.1177/0091270004270833

Bosentan is a dual endothelin receptor antagonist in development for the treatment of pulmonary arterial hypertension in Japan, whereas it is registered for this indication in Europe and the United States. The present study was conducted to compare the pharmacokinetics of bosentan in Caucasian and Japanese subjects. In a double‐blind, placebo‐controlled, ascending single‐dose, 5‐way crossover study, 10 healthy Caucasian and 10 Japanese subjects (1:1 male/female ratio) received single doses of 31.25, 62.5, 125, and 250 mg of bosentan or placebo. Pharmacokinetic profiles of bosentan and its pharmacologically active hydroxy metabolite, Ro 48–5033, were determined after each dose of bosentan. The pharmacokinetics of bosentan were similar and dose proportional in both ethnic groups. However, peak plasma concentration values of Ro 48–5033 were significantly greater in Japanese subjects (P < .05). This difference could not be explained by the lower body weight of the Japanese subjects. Females in both groups tended to have higher exposure to both bosentan and Ro 48–5033 than males. The results suggest that, based on pharmacokinetic grounds, no dose adjustment of bosentan is necessary when used to treat Japanese patients in comparison to Caucasian patients.