Relative oral bioavailability of microgranulated amoxicillin in pigs

Abstract

A new microgranulated formulation of amoxicillin trihydrate for in-feed medication was developed using a lipogelled matrix. Its relative bioavailability was compared with powdered drug in pigs and an assessment was made to determine whether therapeutic concentrations were achieved. Microgranules containing 10% (MICR10) and 30% (MICR30) amoxicillin and free amoxicillin trihydrate powder (reference, AMX) were administered at dosages of 50 mg of amoxicillin/kg b.w. using a three-way-crossover design. Amoxicillin analysis in serum was performed by a sensitive high performance liquid chromatography (HPLC) method with fluorometric detection, using an extraction procedure already described for edible tissues of fish and adapted and validated for pig serum. The oral bioavailability of both microgranulated formulations was higher than that of the reference formulation [relative bioavailability (F): 153.9 +/- 58.2% for MICR10; 126.2 +/- 70.5% for MICR30] and the area under the concentration-time curve (AUC) values of MICR10 and AMX formulations were significantly different (P < 0.05). Differences between the mean maximum concentration (Cmax), time of Cmax (tmax) and mean residence time (MRT) of the drug formulations were not significant. Microgranulated amoxicillin is suitable for in-feed administration to pigs and, because of its higher oral bioavailability compared with the powdered compound, it may be more effective for the treatment of susceptible infections.

Comparative Veterinary Pharmacokinetics

“…Thus, increasing dosage decreases oral bioavailability, as described in humans (Arancibia et al, 1988). When using an microencapsulated granule formulation, bioavailability is significantly increased to nearly 100%, that might be an explanation as microencapsulation protects amoxicillin from enzymatic degradation (Anfossi et al, 2002).…”

Bioequivalence study of two oral amoxicillin formulations (Biocillin® and Atcomox 87%®) in broiler chickens

“…Knowledge of the route of removal, metabolic paths and the degree of efficiency are vital informations for the right dosage, which protects the body against potential drug toxicity. 5,6 The bioavailability and bioequivalence studies play an important role in determining therapeutic efficacy to register the generic drug products according to the Food and Drug Administration (FDA) regulations.…”

Quantitative analysis of amoxicillin, its major metabolites and ampicillin in eggs by liquid chromatography combined with electrospray ionization tandem mass spectrometry

“…They have bactericidal activity and inhibit bacterial cell-wall biosynthesis by binding to enzymes in the cell wall (Anfossi, Zaghini, Grassigli, Menotta, & Fedrizzi, 2002;Hou & Poole, 1971). However, the use of sub-therapeutic doses of antibiotics in food-producing animals to increase bulk may result in the presence of undesirable residues in food (e.g., milk, meat and eggs), which represent a potential risk to individuals with hypersensitivity to penicillin.…”