RESUMO
The bioavailability and pharmacokinetic disposition of tiamulin in broiler chicken were investigated after administration through the crop, drinking water, and feed at 40 mg/kg body weight. Residues of tiamulin in tissues of broiler chicken were also assessed. Plasma and tissue concentrations of tiamulin were analyzed by reverse-phase high-performance liquid chromatography (HPLC) method. Plasma concentration-time data were described by the non-compartmental model for all three routes, and pharmacokinetic parameters were calculated. There were no significant differences (p > 0.05) in pharmacokinetic parameters and mean plasma concentrations of tiamulin between three routes tested (crop, water, and feed), indicating equal efficacy. Tiamulin residues in edible tissues (muscles, skin, and fat) were lower than the advocated maximum residue limit (MRL of 0.1 µg/g and that of liver was 1 µg/g) on the 3rd day. No traces were found on the 5th day after drug administration. This indicated that the withdrawal period (less than 5 days) is very short, which makes it safer. This study shows that tiamulin can be used with equal efficacy through all routes of administration in broiler chicken (crop, water, and feed).
Assuntos
Antibacterianos/farmacocinética , Galinhas/metabolismo , Animais , Antibacterianos/administração & dosagem , Antibacterianos/sangue , Área Sob a Curva , Disponibilidade Biológica , Galinhas/sangue , Diterpenos/administração & dosagem , Diterpenos/sangue , Diterpenos/farmacocinética , Vias de Administração de Medicamentos , Resíduos de Drogas , Farmacorresistência Bacteriana , Meia-Vida , Mycoplasma gallisepticum/efeitos dos fármacosRESUMO
Silymarin, a polyphenolic flavonoid isolated from milk thistle (Silybum marianum), is being used clinically in Europe and Asia for the treatment of liver diseases. Silymarin has a strong antioxidative action capable of scavenging both free radicals and reactive oxygen species responsible for cancer. Silymarin, a powerful hepatoprotective and antioxidant, was chosen in the present study and was tested for its antimutagenic activity using an in vitro test, the Ames bacterial reverse mutation assay. The results indicated that silymarin showed a significant mutagenicity in frame shift mutant strains (TA97a and TA98) with metabolic activation. This compound also showed stronger antimutagenic effect against 2-aminofluorene and 4-nitroquinoline N-oxide induced mutation. When pre-, co- and post-treatment of silymarin was carried out, it showed stronger antimutagenic activity in the post-treatment with 2-aminofluorene and 4-nitroquinoline N-oxide in TA97a and TA98 strains.