Liquid chromatographic determination of efficacy of incorporation of trimethoprim and sulfamethoxazole in brine shrimp (<i>Artemia</i> spp.) used for prophylactic chemotherapy of fish
The brine shrimp Artemia , an excellent live food source in aquaculture, has been studied as a carrier to deliver selected chemotherapeutic agents to fish for prophylactic treatment of infectious diseases. To monitor the efficiency of incorporation of trimethoprim and sulfamethoxazole in Artemia franciscana, a sensitive and specific analytical method was developed. It is based on homogenization of Artemia nauplii in methanol, extraction of lipids with hexane, solid-phase cleanup on C18 cartridges, and reversed-phase liquid chromatography with detection at 210 nm. The method is sensitive (detection limit, on the order of 3 µg/g with a sample quantity of 30 mg [dry weight]) and reproducible (coefficients of variation, 2.2 and 1.8% for trimethoprim and sulfamethoxazole at levels of 79.6 and 257 µg/g of body weight, respectively). Preliminary quantitative data indicated excellent uptake and persistence of both therapeutic agents in A. franciscana, with levels of 115 µg/g for trimethoprim and 277 µg/g for sulfamethoxazole
