Abstract: AIM: To investigate the pharmacokinetics of fosphenytoin sodium injection at single dose in Chinese healthy volunteers. METHODS: The pharmacokinetics of intravenous infusing fosphenytoin sodium injection at different dose levels (600 mg and 900 mg) was studied in 24 healthy volunteers.The drug concentrations in plasma samples were assayed by HPLC, and the pharmacokinetic parameters were calculated by DAS 2.0 software. RESULTS: Among 24 healthy subjects, the main pharmacokinetic parameters of fosphenytoin after single dose of 600 mg and 900 mg were as follows: C_max were (89.3±14.9), (110.5±17.2) mg/L; t_max were (0.46±0.08), (0.46±0.08) h; AUC_0-t were (56.5±11.3), (71.2±13.8) mg·h·L^-1; for phenytoin, they were C_max (8.36±0.92), (11.98±1.07) mg/L; t_max (1.1±0.3), (1.3±0.3) h; AUC_0-t(222.7±47.8), (355.9±72.6) mg·h·L^-1, respectively. CONCLUSION: After 600-900 mg single dose infusion of fosphenytoin sodium injection, the pharmacokinetic results show that both fosphenytoin and phenytoin exhibit first order kinetic characteristics in such a dose. And the pharmacokinetic characteristics of fosphenytoin sodium injection are consistent with foreign reports.

Key words: fosphenytoin, pharmacokinetics, HPLC