Bioaccumulation of trimethoprim, sulfamethoxazole and N-acetyl-sulfamethoxazole in Artemia nauplii and residual kinetics in seabass larvae after repeated oral dosing of medicated nauplii.

摘要

The pharmacokinetics of trimethoprim (TMP), sulfamethoxazole (SMX) and its metabolite N-acetyl-sulfamethoxazole (N-acetyl-SMX), were studied in Artemia nauplii as a function of the duration and temperature of their storage, following their enrichment with the therapeutics using the bioencapsulation technique. A decrease in the therapeutic content of the nauplii was observed upon storage at 18deg C and 25deg C and it is suggested that medicated nauplii should either be administered fresh to fish larvae orafter storage for 8 h at 5deg C, at the most. Under the latter conditions, satisfactory levels of TMP and SMX were achieved, high survival rates and dry weight contents of the nauplii were preserved and minimal leakage of the therapeutics to the environment was secured. Treatment of sea bass larvae with 1, 3, 6 or 10 doses of medicated Artemia nauplii, showed that maximum levels of the therapeutics are achieved in fish larvae when 10 doses are used. Following the treatment scheme of oral administration of10 doses of medicated Artemia nauplii to fish larvae, the residual kinetics of TMP, SMX and N-acetyl-SMX were studied in sea bass larvae. TMP and SMX showed different kinetic characteristics. A steady state of SMX concentration was achieved in fish bodytissue during the 5-day medication period. TMP, SMX and N-acetyl-SMX were detectable in small amounts in fish body tissue even 100 h after treatment. It is concluded that oral medication of fish larvae through the use of Artemia nauplii as a carrier oftherapeutics, appears to be a promising approach to be used as an alternative method of treatment.