DRUG ASSIMILATION IN THE TISSUE OF EUROPEAN SEA BASS (DICENTRARCHUS-LABRAX) FRY DELIVERED ORALLY THROUGH BIOENCAPSULATION

Assimilation levels of the antibacterials trimethoprim (TMP) and sulfa methoxazole (SMX) in sea bass (Dicentrarchus labrax) fry tissue admini stered orally were investigated. A 1:5 TMP and SMX combination incorpo rated in an oil emulsion (Selco) at 20 % and 40 % concentrations (w/w) were bioencapsulated in Artemia (Instar II) nauplii. Chemotherapeutic s-loaded ('medicated') nauplii were fed to the sea bass fry and drug c oncentrations in the tissue were analysed by high-performance liquid c hromatrography (HPLC). Fish fed 40 % 'medicated' Artemia assimilated s ignificantly higher levels of chemotherapeutics compared with those fe d 20 % 'medicated' Artemia. Chemotherapeutics given at 40 % reached pe ak levels (19.3 mu g TMP/g DW and 23.31 mu g SMX/g DW) within 2 h whil e those at 20 % peaked (8.74 mu g TMP/g DW and 6.73 mu g SMX/g DW) aft er 5 h. TMP persisted in the tissues longer (up to 72 h) than SMX (12- 16 h), suggesting a more efficient uptake and retention of the former and/or faster metabolism and elimination of the latter.