Valutazione della biodisponibilità di amoxicillina microincapsulata e micronizzata a seguito di somministrazione orale singola nel branzino (Dicentrarchus labrax)

In order to reduce the disadvantages linked to antimicrobial therapy to fish (poor absorption of drugs, very high doses administered that ultimately ends up in the water environment) a research in seabass (Dicentrarchus labrax) was undertaken with the purpose to improve the oral bioavailability of amoxicillin (AMX) exploiting techniques of microencapsulation and micronization. The bioavailabilities of the drug from the microencapsulated and micronized formulations added to feed were compared with this of commercial medicated feed (AMX conventional). These medicated diets were fed at 1% of the biomass, so administering 80 mg/kg b.w. as nominal doses of the antibacterial. Blood samples were collected at different intervals of time up to six days after single administration and the sera obtained by centrifugation were analysed by HPLC methods. The area under concentration-time curves (AUC) were found to be equal to 8.03 μg/ml/h for AMX micronized, 9.40 μg/ml/h for AMX conventional and 15.07 μg/ml/h for AMX microencapsulated. The improvement of the bioavailability of AMX from the micro-encapsulated form was achieved as demonstrated by the relative (encapsulated form vs. conventional one) F% value: 160.31% .