Liquid chromatographic determination of efficacy of incorporation of Trimethoprim and Sulfamethoxazole in Brine Shrimp (Artemia spp

,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 disases. 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 chromatog-raphy wvith detection at 210 nm. The method is sensitive (detection limit, on the order of 3 pg/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,ug/g of body weight, respectively). Preliminary quattative data indicated excellent uptake and persistence of both therapeutic agents in A. franciscana, with levels of 115,ug/g for trimethoprim and 277,ug/g for sulfamethoxazole. The world's supply of fish and other aquatic organisms is becoming increasingly dependent on aquaculture (17). How-ever, the success of large-scale fish and shrimp farming is commonly jeopardized by the occurrence of infectious dis-eases, often leading to high mortalities and, hence, seriou