Pharmacokinetics and bioequivalence study of tetramethylpyrazine phosphate tablets after single-dose administration in healthy Chinese male subjects .

Background: Tetramethylpyrazine, isolated from Ligusticum wallichii Franch., is widely used for the treatment of cerebrovascular and cardiovascular diseases in China.

Objective: To assess and compare the pharmacokinetic characteristics and bioequivalence of two tetramethylpyrazine phosphate (TMPP) tablets in healthy Chinese male subjects.

Materials And Methods: 20 healthy male subjects were randomly divided into two groups according to a two-period crossover design test. A single oral dose of 200 mg test or reference tablets was given with a 7-day washout period under fasting conditions. Blood samples were taken at scheduled time points, and the concentration of TMPP was measured by LC-MS. Drug And Statistical Software-Version 2.0 was used to calculate the pharmacokinetic parameters and assess bioequivalence of the two formulations.

Results: 20 subjects were enrolled in the study, and none dropped out. The main pharmacokinetic parameters of test and reference formulations were as follows: T1/2 was (1.79 ± 0.82) hours and (1.64 ± 0.52) hours, tmax was (0.76 ± 0.37) hours and (0.94 ± 0.44) hours, Cmax was (961.14 ± 309.64) ng/mL and (1,059.09 ± 350.69) ng/mL, AUC0-12h was (1,744.69 ± 643.49) ng×h/mL and (1,726.32 ± 494.11) ng×h/mL, AUC0-∞ was (1,756.95 ± 643.63) ng×h/mL and (1,740.16 ± 504.89) ng×h/mL, respectively. The relative bioavailability of TMPP tablets was 102.4 ± 26.0%, and no serious adverse events were reported.

Conclusion: This single-dose study in healthy Chinese male fasted subjects showed that the TMPP test and reference tablets were bioequivalent.
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