Assessment of the Pharmacokinetics of a Sustained Release Formulation of a Tramadol/Acetaminophen Combination

This study was open, randomized, 2-period, 2-treatment multiple-dose crossover study of immediate release treatment and sustained release treatment was designed to assess the pharmacokinetics after a 2-day repeated administration in which the steady state was achieved.

Inclusion criteria

• Subjects between the ages of 20 and 45 years
• Subjects weighed ≥ 45 kg and were within 20% of their ideal body weight
• No clinically relevant abnormalities identified by vital sign measurement, 12-lead electrocardiography and routine laboratory test

Exclusion criteria

• Hypersensitivity or histories of sensitivity to either tramadol or acetaminophen
• Evidence or histories of clinically significant renal, digestive, respiratory, musculoskeletal, endocrine, psychiatric, neurological, hematological or cardiovascular diseases
• Taking any prescription or herbal medicines within 2 weeks before the study or any over-the-counter medication within 1 week before the study
• Systolic blood pressure (SBP) ≥ 160 mmHg or ≤ 100 mmHg or diastolic blood pressure (DBP) ≥ 95 mmHg or ≤ 60 mmHg
• Any surgical or medical conditions that could affect drug absorption