Influence of a pig respiratory disease on the pharmacokinetic behaviour of amoxicillin after oral ad libitum administration in medicated feed

Abstract

The pharmacokinetic properties of amoxicillin in healthy and respiratory-diseased pigs were studied, after ad libitum administration of medicated feed. In addition, amoxicillin dose linearity and drug penetration into respiratory tract tissues were evaluated in diseased animals. The respiratory disease involves porcine reproductive and respiratory syndrome virus and bacterial agents such as Pasteurella multocida, Bordetella bronchiseptica and Streptococcus suis. Typical clinical signs and gross lesions of respiratory disease were observed. The plasma pharmacokinetic analysis was performed by means of a noncompartmental approach. After single intravenous bolus administration of amoxicillin to healthy pigs, the steady-state volume of distribution was 0.61 L/kg, the total plasma clearance was 0.83 L/h/kg and the mean residence time was 0.81 h. After oral bolus administration, the mean absorption time was 1.6 h and the peak plasma concentration (3.09 μg/mL) reached at 1.1 h postadministration. The oral bioavailability was 34%. For oral ad libitum administration, plasma concentration-time profiles were related to the feeding behaviour. Plasma concentrations at steady-state were established between 12 and 120 h. The pharmacokinetic parameters calculated (C(maxss) , C(minss) , C(avss) and AUC(24ss) ) showed significantly lower values in healthy pigs compared to diseased animals. This was in accordance with the significantly higher amoxicillin bioavailability (44.7% vs. 14.1%) and longer absorption period observed in diseased pigs. Amoxicillin dose linearity in diseased animals was established in a dose range of 4-18 mg/kg. On the other hand, tissue distribution ratio in diseased animals was 0.65 for bronchial mucosa, 0.48 for lung tissue and 0.38 for lymph nodes. Our results suggest that the pharmacokinetic properties and disposition of amoxicillin can be influenced by the disease state or by related factors such as changes in the gastrointestinal transit.

Clinical Efficacy and Residue Depletion of 10% Enrofloxacin Enteric-Coated Granules in Pigs

“…For the WDT of ENR, our findings in pigs were 5 days, which was similar to 5 or 6 days in poultry in previous reports (San Martin et al, 2010; Terrado-Campos et al, 2017). The previous studies revealed that after exposure to ENR at a dose of 10 mg/kg, the WDT was 5, 7, and 10 days in pigs (Delsol et al, 2004; San et al, 2007; Liu et al, 2011), and 23 days in piaractus mesopotamicus (Luo et al, 2010), most of which was far longer than that in our study (Wiuff et al, 2002; San et al, 2007; Godoy et al, 2011; Paschoal et al, 2013). Therefore, EEG had an advantage with a short WDT.…”

“…Previous reports had established a close link between the respiratory disease risk and the productivity decrease in animals (Godoy et al, 2011; Paschoal et al, 2013; Hassanpouraghdam et al, 2015; Sala et al, 2015). Generally, the strain with MIC 95 or MIC 90 was the preference for establishment of infection model and indicators for clinical treatment.…”

Amoxicillin—current use in swine medicine

“…Godoy et al. () also confirmed amoxicillin plasma concentrations were also higher in respiratory disease affected pigs after oral administration of amoxicillin. This suggests that the PK results in healthy pigs might underestimate the plasma concentrations and the time above MICs achieved and thereby a better treatment effect might be seen.…”

Combined effect of amoxicillin and sodium fluoride on the structure of developing mouse enamel in vitro

“…A study on pigs showed that with the same amoxicillin dose serum amoxicillin levels were significantly lower in healthy pigs than in diseased animals suffering from a respiratory infection. 33 Organ cultures lack the impact of infection-related factors, which may potentiate the effects of chemical compounds. Thus the effect of a single factor, here NaF or amoxicillin, may be weak unless high exposure concentrations are used.…”