Residues and Elimination of Norfloxacin in Tissues from Fenneropenaeus chinensis Following Different Forms Administration

The residues and elimination of norfloxacin(NFLX) were studied in tissues from fennerropenaeus chinensis following water administration and oral administration at(28±1)℃.The norfloxacin analysis was performed by RP-HPLC.There was great difference between elimination of norfloxacin in tissues after water administration and oral administration.Peak concentration(Cmax) and time of occurrance of that value(Tmax) in hepatopancreas following water administration(10 mg/L)were 1.36 μg·g-1 at 9 h,while the corresponding values in muscles were 0.25 μg·g-1 at 24 h.Peak concentration(Cmax) and time of occurrence of that value(Tmax) in hepatopancreas following oral administration(30 mg/kg) were 0.79 μg·g-1 at 4 h,while the corresponding values in muscles were 0.113 μg·g-1 at 4 h.Elimination equations in muscle following the two exposure techniques were C(t)water=0.2449e-0.4138t and C(t)oral=0.4066e-0.5364t;while elimination half-lives were 40.19 h and 31.01 h.According to the residue limit standard(50 μg·kg-1) of norfloxacin in aquatic products,the concentration of norfloxacin in muscle were both lower than the residue limit standard after 24 h following the two exposure techniques;the concentration of norfloxacin in hepatopancreas was lower than the residue limit standard after 216 h following water administration while after 96 h following oral administration.The withdrawal time of norfloxacin in muscle was 3.84 d following water administration while 3.90 d following oral administration.