Pharmacokinetics of multiple doses of co‐crystal of tramadol–celecoxib: findings from a four‐way randomized open‐label phase I clinical trial

Aim We compared the pharmacokinetic (PK) profiles of co‐crystal of tramadol–celecoxib (CTC) vs. each reference product (alone and in open combination) after single (first dose) and multiple dosing. Methods Healthy adults aged 18–50 years received, under fasted conditions, 15 twice‐daily doses of the following treatments (separated by ≥14‐day washout): 200 mg immediate‐release (IR) CTC (equivalent to 88 mg tramadol and 112 mg celecoxib; treatment...