Obj

ective    To assess the pharmacokinetic profiles of compound propyphenazone and diphenhydramine tablets by LC-MS.     Methods    The single dose study was conducted in 12 healthy volunteers taking one

two

or three tablets of compound propyphenazone and diphenhydramine tablets (each containing propyphenazone 220 mg

diphenhydramine 20 mg) in one week

then another dose at the next week and so on. The multiple dose study was performed in another 12 healthy volunteers taking one tablet every 8 hours for 10 times. The plasma and urine concentrations of propyphenazone and diphenhydramine were measured by LC-MS method.     Results    The major pharmacokinetic parameters of diphenhydramine for the multiple and single dose study were as follows: C

max

were (143.75±33.995) μg/L and (63.608±56.908) μg/L

t

1/2z

were (16.619±26.588) h and (9.507±4.932) h; AUC

0-t

were (1 226.022±476.67) h·μg/L and (470.161±219.52) h·μg/L; The major pharmacokinetic parameters of propyphenazone for the multiple and single dose study were as follows: C

max

were (3 220±1 304.781) μg/L and (3 252.083±1 135.837) μg/L

t

1/2z

were (3.029±1.856) h and (2.826±1.211) h; AUC

0-t

were (6 522.007±1 714.091) h·μg/L and (8 055.037±2 418.651) h·μg/L; The steady-state pharmacokinetic parameters of diphenhydramine were as follows: C

maxss

was (143.75±33.995) μg/L

C

minss

was (49.225±39.187) μg/L

C

avss

was (65.399±14.942) μg/L

DF was (1.627±0.532)

R was (3.098±1.444). The steady-state pharmacokinetic parameters of propyphenazone were as follows: C

maxss

was (3 320.0±1 304.781) μg/L

C

minss

was (151.211±138.197) μg/L

C

avss

was (749.052±183.166) μg/L

DF was (4.255±1.294)

R was (1.222±0.800).     Conclusion    There is significant difference in pharmacokinetic parameters of compound propyphenazone and diphenhydramine tablets (220 mg/20 mg)  between single and multiple dose administration. There is significant acumulation after admin

istering one tablet every 8 hours.