The present study was adopted to evaluate the pharmacokinetics and dose linearity of fexofenadine after oral administration.

The present study was adopted to evaluate the pharmacokinetics and dose linearity of fexofenadine after administration of single oral doses of 60 to 360 mg in an open-label, five-way crossover study.

Inclusion Criteria:

• At least 18 years old and not more than 45 healthy male volunteers
• Actual weight no more than ± 30% from ideal body weight based on sex, height, and body frame
• Who had passed all the screening parameters
• Free of any drug exposure known to interfere with the pharmacokinetics or assay of fexofenadine for at least 10 days prior to the study
• Who had to be able to communicate effectively with study personnel, be literate, and able to give consent.

Exclusion Criteria:

• A clinically significant abnormal physical exam, medical history, or laboratory studies
• If they showed a sitting SBP of >140 or <100 mmHg, DBP > 90 or <60mm Hg, or a pulse rate of > 95 or < 50 beats/min at screening
• A history of serious intolerance, allergy, or sensitivity to fexofenadine
• The use of any prescription drug within the previous month or use of any over-the-counter medication (with the exception of acetaminophen) within the past 14 days
• A history of blood dyscrasias
• A history of alcohol or drug abuse within the past year
• Donation of blood during the 8 weeks prior to the study or plans to donate blood during or within 8 weeks of completing the study
• Unable to tolerate vein puncture and multiple blood samplings
• Any surgical/medical condition that might alter drug absorption, distribution, metabolism, or excretion
• Cannot follow instructions, in the opinion of the investigator.