Pharmacokinetic Study and Bioequivalence Evaluation of Two Sustained‐Release Tablets of Tamsulosin in Healthy Chinese Subjects Under Fasting and Postprandial Conditions

Tamsulosin is a highly selective α1A adrenergic receptor antagonist that can relax smooth muscles in the urethra, bladder neck, and prostate and improve urinary disorders. It is therefore widely used to treat lower urinary tract symptoms caused by benign prostatic hyperplasia. The aim of this study is to evaluate the pharmacokinetic (PK) characteristics and bioequivalence of 2 different formulations (tamsulosin sustained-release tablets and tamsulosin sustained-release capsules) in healthy Chinese subjects. This study was a single-center, randomized, open label, 2-formulation, single-administration, 2-cycle, double-crossover fasting/postprandial bioequivalence trial that included 56 healthy volunteers (28 fasting and 28 postprandial). Blood samples were collected from volunteers after oral administration, plasma concentrations of tamsulosin were determined by liquid chromatography-tandem mass spectrometry for PK analysis, and the safety and tolerability of the drug were monitored. Under fasting and postprandial conditions, the 90% confidence intervals for maximum observed concentration (C_max) and area under the plasma concentration-time curve from time 0 to the last sampling time (AUC_0-t) of the test and reference formulations were within an acceptable range (80%-125%). All adverse events (AEs) were mild and no serious AEs were observed in the study. The subject formulation of tamsulosin extended-release tablets was safe and well tolerated in healthy Chinese Volunteers.