BIOAVAILABILITY OF AMOXICILLIN IN CHICKENS

Abstract

For evaluation of bioavailability of amoxicillin in chickens during prophylactic treatment by salinomycin ( 60 ppm ), 66 one day old chicks were divided into 2 groups, non-treated one (G1) and treated group (G2). Serum concentrations of amoxicillin after single intravenous, oral and intramuscular doses ( 15 mg / kg b.wt. ) were determined. Multiple oral doses (same dose twice daily for 5 consecutive days) were also given for tissue residue studies . Non-compartmental calculations of pharmacokinetic parameters after single intravenous dosing revealed that half-life of distribution ( t 0.5 α ) was 0.19 ± 0.05 h and 0.14 ± 0.03 h, while, half-life of elimination ( t 0.5  ) was 2.57 ± 0.07 h and 2.06 ± 0.08 h in G1and G2 , respectively . Central volumes of distribution of amoxicillin (Vc) were 0.20 ± 0.03 and 0.19 ± 0.04 L/kg , respectively . Area under curve (AUCIV) was 95.74 ± 4.22 mg.h/L in G1 and significantly decreased to 74.76 ± 3.24 mg.h/L in G2 , respectively . Mean residence times (MRT) were 3.35 ± 0.73 and 2.67 ± 0.81 hours in G1and G2, respectively .After single oral dose maximum concentration ( C max ) , maximum time ( T max ), MRT and bioavailability ( F%) were 0.99 ± 0.06 and 0.89 ± 0.08 μg/ml , 3.25 ± 0.35 and 3.48 ± 0.14 hours , 8.19 ± 1.08 and 7.48 ± 0.85 hours , 20.41 ± 2.05 and 23.87± 1.51 % in G1 and G2 , respectively . After single intramuscular dose C max , T max, MRT and F% were 0.89 ± 0.14 , 0.85 ± 0.13 μg/ml 1.85 ± 0.24 and 1.88 ± 0.15 h , 7.23 ± 1.88 and 6.21 ± 2.13 h, 12.28 ± 1.82 h and 13.42± 2.21% in G1and G2 , respectively . Prophylactic dose of salinomycin slightly improved bioavailability of amoxicillin in chickens.