Pharmacokinetic Analysis
The pharmacokinetics of tacrolimus was evaluated within seven days after the enrollment, based on the drug levels in 13 blood samples (3 mL each) collected at 0 (pre-dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 9, 12, 16, 20, and 24 h after the morning dose. All blood samples were collected to ethylenediaminetetraacetic acid-containing Vacutainer® tubes. and were stored at 4°C until the analysis was carried out on the same day. The trough levels (C0 and Cmin) were measured just before tacrolimus administration; peak tacrolimus concentration (Cmax) for each subject was obtained directly from the raw data. The area under the curve (AUC) was estimated using the linear trapezoidal method from hours 0 to 24.