Abstract: AIM: To establish a method to investigate pharmacokinetics and bioequivalence of buthlphthalide injection. METHODS: An open, randomized, and two-cycle crossover study was conducted in 24 healthy volunteers. Plasma concentrations of buthlphthalide were determined by LC-MS/MS after administering a single dose of reference drug or test drug. Main pharmacokinetic parameters were calculated by Phoenix WinNonlin 6.4 software. RESULTS: For the test drug and the reference drug, the main pharmacokinetic parameters of flurbiprofen were as follows: AUC0-t was (541.0±78.6) ng·mL-1·h and (525.0±76.1) ng·mL-1·h, AUC0-∞ was (571.0±82.1) ng·mL-1·h and (555.0±88.1) ng·mL-1·h, Cmax was (295.0±62.7) ng/mL and (291.0±56.5) ng/mL, and the median of Tmax was 0.92 (0.33, 0.92) h and 0.92 (0.33, 0.93) h, respectively. Under two kinds of conditions, 90%CIs of AUC0-t, AUC0-∞ and Cmax of the test preparation were 80%-125% of the corresponding parameters of the reference preparation，and there was no statistical significance in Tmax between the two preparations (P＞0.05)．CONCLUSION: The test drug and the reference drug are bioequivalent．

Key words: buthlphthalide injection, HPLC-MS/MS, bioequivalence