G. Castells

Characterization of the degradation performance of the sulfamethazine antibiotic by photo-Fenton process.

The present study provides results describing the degradation performance of the Sulfamethazine (SMT) antibiotic via photo-Fenton treatment. Experiments were carried out using 1 L solution samples of SMT (50 mg L(-1)) under different conditions. HPLC results reveal that both Fenton and photo-Fenton reactions were able to completely remove SMT antibiotic from the studied samples in less than 2 min treatment. Half-life times and kinetic parameters (assuming a pseudo-first-order kinetics at reaction initial stage, far from the equilibrium) for SMT degradation were determined and discussed. Hence, appropriate Fenton reagent loads are given to attain different targets proposed. TOC and HPLC data also revealed the presence of reaction intermediates; thus toxicity assays were performed regarding bacterial growth rate. The toxicity of an SMT solution was shown to increase during its degradation by means of photo-Fenton reactions.

Albendazole sulphoxide enantiomers in pregnant rats' embryo concentrations and developmental toxicity.

Three single oral doses (8.5, 10, and 14 mg/kg) of a racemic formulation of albendazole sulphoxide (ABZSO) were administered to pregnant rats on day 10 of gestation. Mother plasma and embryo concentrations of ABZSO enantiomers and albendazole sulphone (ABZSO(2)) were determined 9 h after administration. The (-)-ABZSO enantiomer showed higher peak concentrations in both maternal plasma and embryo than the (+) enantiomer. An increase in embryo concentrations of ABZSO enantiomers and ABZSO(2) was only observed when dose rose to 14 mg/kg. There was an increase in resorption when the dose increased, but significant differences were only found in the higher dose group when compared with the other groups. The incidence of external and skeletal malformations (mostly of the tail, vertebrae and ribs) rose significantly in the 10 mg/kg group, producing almost 20% and 90% of malformed fetuses, respectively, and gross external and skeletal abnormalities in the thoracic region and limbs were also found.

Effect of age and gender in the pharmacokinetics of albendazole and albendazole sulphoxide enantiomers in goats

The kinetics of albendazole metabolites and albendazole sulphoxide enantiomers were studied in 2- and 14-month-old female and male goats, after a single oral dose administration (10mg/kg) of an albendazole formulation. Blood samples from the jugular vein were collected at 0.5, 1, 2, 4, 6, 8, 10, 12, 16, 20, 24, 30, 36, 42, 48 and 54h post-treatment and analyzed using a high performance liquid chromatography method. In all groups the area under the plasma concentration-time curve (AUC) and peak concentration (C(max)) values of (+)-ABZSO were significantly higher than those of (-)-ABZSO. The AUC and C(max) values obtained for (+)-ABZSO and (-)-ABZSO in adult animals were higher compared to the results in young animals, showing significant differences except for (+)-ABZSO in female animals. In young animals, independently of gender, the C(max) appeared earlier compared to adult animals. The mean residence time (MRT) values were shorter in young animals compared to adult animals for all compounds analyzed. No sex-related differences were found for any of the parameters calculated except for the (+)-ABZSO from adult animals.

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

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.