Liposome mediated delivery of water soluble antibiotics to the larvae of aquatic animals

Large phospholipid vesicles loaded with the water soluble antibiotic oxytetracycline were formed using the reverse phase evaporation technique. Addition of cholesterol in the lipid phase and suspension of the liposomes in low pH solutions, greatly improved stability of the liposomes upon storage. Liposomised oxytetracycline was administered to Anemia franciscana nauplii using the bioencapsulation technique. Survival and larval development of the nauplii was not affected by the presence of liposomes in the enrichment medium. Determination of oxytetracycline levels in the liposomal preparations and in the nauplii, using reverse phase high performance liquid chromatography, showed significant amounts of antibiotic in the nauplii. The uptake of the liposomised antibiotic by the nauplii depended on the amount of the administered antibiotic and the duration of the enrichment period.