Standardization of the bioencapsulation of enrofloxacin and oxytetracycline in Artemia franciscana Kellogg, 1906

Bioencapsulation of enrofloxacin and oxytetracycline into Artemia francisca na nauplii was standardized. Both antibacterials were delivered to the naup lii individually and the amounts used in the study were percentages of the lipid emulsion Rich((R)) added as nutrition enrichment for the nauplii. The determination of the amounts of drug incorporated in A, franciscana naupli i was obtained using a bioassay radial diffusion method, standardized in th e laboratory and using Escherichia coli as an indicator. The minimum time f or full enrichment for both enrofloxacin and oxytetracycline bioencapsulati on in A. franciscana nauplii was 4 h after the initial exposure of the naup lii to the antibiotics and this was established sampling nauplii at 1, 2, 3 , 4, 8 and 24 h after adding the nauplii to the mix. These experiments were carried out twice and at 4 h, 1.10 and 1.13 ng of enrofloxacin per naupliu s and 9.32 and 9.37 ng of oxytetracycline per nauplius were obtained. The o ptimum percentages of enrichment were 40% of enrofloxacin in relation to Ri ch((R)) and 80% of oxytetracycline. The percentages tested were 10%, 20%, 3 0%, 40% for the enrofloxacin and 0%, 40%, 80%, and 160% for the oxytetracyc line. The maximum time at which antibiotic was still detected in the Artemi a after it had been introduced in seawater was 8 h for both antibacterial a gents. (C) 2001 Elsevier Science B.V. All rights reserved.