Abstract: AIM:To develop a gas chromatography- mass spectrography method for the determination of Bro- moxynil in rabbit plasma, and to study the toxicokinetics of Bromoxynil in rabbits .METHODS:Seven male rab- bits were involved in the study .Each subject received a single dose of 30 mg·kg^-1 Bromoxynil tested formulation . Blood samples were conducted consequently within 72 hours .The plasma Bromoxynil concentrations were deter- mined by GC-MS .The plasma Bromoxynil concentration were calculated by ADS and calculated the toxicokinetics parameters.RESULTS:After a single dose of 30 mg·kg ^-1 tested formulation, the oxicokinetics parameters of Bromoxynil were as following :t_{1 /2ke} was 11 ±3 hours, · 102 · Chin J Clin Pharmacol Ther 2006 Jan;11( 1) T_max 5 .6 ±1 .2 hours, C_max 110 ±43 mg·L ^-1 , AUC_{0 -tn} 2275 ±959 mg·L ^-1·h^-1 and AUC_{0 -∞} 2315 ±980 mg·L ^-1·h^-1 , MRT_0-tn 16 .9 ±2 .5 hours, and MRT_{0 -∞} 18 .1 ±2 .9 hours .CONCLUSION:After 30 mg·kg ^-1 ig administration demonstrates that plasma Bromoxynil concentration against time profile is fitted well to the one- compartment open model with 1st order absorption .Ab- sorption and elimination of Bromoxynil in rabbits were all slow.The method for determination of Bromoxynil con- centration in plasma by GC-MS is simple, sensitive, and accurate .

Key words: Bromoxynil , toxicokinetics , gas chrom- atography-mass spectrum ( GC-MS) , intoxication