Pharmacokinetic and Safety Comparison of Two Capecitabine Tablets in Patients With Colorectal or Breast Cancer Under Fed Conditions: a Multicenter, Randomized, Open-label, Three-period, and Reference-replicated Crossover Study

This was a multicenter, open, random, balanced, three-period, three-sequence and semi-repetitive cross study with 48 subjects. Eligible subjects were randomly assigned in a 1:1:1 ratio to receive one period of test formulation or two period of reference formulation, followed by a 1-day washout period and administration of the alternate formulation. Serial blood samples for pharmacokinetic assessment were collected at 0 hours (predose) up to 8 hours postdose. The plasma concentrations of capecitabine were analyzed by LC/MS-MS. Pharmacokinetic parameters (non-compartmental model) were assessed with WinNonlin software. The pharmacokinetic parameters assessed were area under the plasma concentration-time curve from time 0 to the time of last measurable concentration (AUC0-t), AUC from time zero to infinity (AUC0-∞), the peak plasma concentration of the drug (C max ), time needed to reach maximum concentration (Tmax), the elimination half-life (t1/2), and terminal elimination rate (λz). All were analyzed using an ANOVA model after logarithmic transformation of the data. For establishing bioequivalence (BE) for capecitabine， reference-scaled average bioequivalence (RSABE) acceptance criteria and average bioequivalence (ABE) acceptance criteria were used. Safety and tolerability was assessed during the entire study period.