Propuesta de una dosis de marbofloxacina para el tratamiento de infecciones asociadas a Escherichia coli en cabras de tres semanas de vida

Se estimó una dosis de marbofloxacina (MFX) para tratar infecciones gastrointestinales asociadas a Escherichia coli en cabras de tres semanas de vida. La farmacodinamia de MFX sobre E. coli se evaluó in vitro estimando las concentraciones inhibitoria mínima (CIM), bactericida mínima (CBM) y preventiva de mutantes (CPM). Marbofloxacina se administró en cabras de tres semanas de edad por vía subcutánea a una dosis de 2 mg/kg. Los parámetros farmacocinéticos se estimaron mediante análisis no compartimental. La dosis de MFX capaz de proteger al 95% de una población se calculó considerando la distribución poblacional de los parámetros farmacocinéticos. La eficacia de MFX se evaluó con la relación entre el área bajo la curva y la CPM (ABC/CPM) con un valor de corte de 22 h. Los resultados mostraron que la dosis estimada de MFX para alcanzar la remisión clínica de infecciones gastrointestinales causadas por E. coli y prevenir la emergencia de cepas resistentes en el 95% de una población de cabras de tres semanas de vida fue de 3,179 mg/kg, que a los fines prácticos se fijó en 3,5 mg/kg.

A dose of marbofloxacin (MFX) to treat gastrointestinal infections caused by Escherichia coli in 3-week-old goats was estimated. The pharmacodynamics of MFX against E. coli was evaluated in vitro by estimation of mínimum inhibitory concentration (MIC), mínimum bactericide concentration (MBC) and mutant prevention concentration (MPC). Marbofloxacin was administered to 3-week -old goats by subcutaneous route at the dose of 2 mg/kg. The pharmacokinetic parameters were estimated by non-compartmental analysis. The dose of MFX capable to protect the 95% of population was calculated considering the population distribution of pharmacokinetic parameters. The efficacy of MFX was evaluated by the relationship between the area under curve and MPC (AUC/MPC) with a cut-off value of 22 h. The results showed that the estimated dose of MFX to reach the clinical outcome of gastrointestinal infections caused by E. coli and to prevent the bacterial resistance at the 95% of the population of 3-week-old goats was 3.179 mg/kg, which for practical reasons was fixed at 3.5 mg/kg.

Pharmacokinetics, efficacy prediction indexes, and residue depletion of ribavirin in Atlantic salmon's (Salmo salar) muscle after oral administration in feed.

Ribavirin is an antiviral used in human medicine, but it has not been authorized for use in veterinary medicine although it is effective against infectious salmon anemia (ISA) virus, between others. In this study, we present a pharmacokinetic profile of ribavirin in Atlantic salmon (Salmo salar), efficacy prediction indexes, and the measure of its withdrawal time. To determine the pharmacokinetic profile, fishes were orally administered with a single ribavirin dose of 1.6 mg/kg bw, and then, plasma concentrations were measured at different times. From the time-vs.-concentration curve, Cmax = 413.57 ng/mL, Tmax  = 6.96 h, AUC = 21394.01 µg·h/mL, t1/2  = 81.61 h, and K10  = 0.0421/h were obtained. Ribavirin reached adequate concentrations during the pharmacokinetic study, with prediction indexes of Cmax /IC50  = 20.7, AUC/IC50  = 1069.7, and T>IC50  = 71 h, where IC is the inhibitory concentration 50%. For ribavirin depletion study, fishes were orally administered with a dairy dose of 1.6 mg/kg bw during 10 days. Concentrations were measured on edible tissue on different days post-treatment. A linear regression of the time vs. concentration was conducted, obtaining a withdrawal time of 1966 °C days. Results obtained reveal that the dose of 1.6 mg/kg bw orally administered is effective for ISA virus, originating a reasonable withdrawal period within the productive schedules of Atlantic salmon.

Depletion study of enrofloxacin and its metabolite ciprofloxacin in edible tissues and feathers of white leghorn hens by liquid chromatography coupled with tandem mass spectrometry.

To ensure delivery of safe foods to consumers, withdrawal times for drugs must be respected according to the maximum residual limits established by regulatory agencies. Because of availability and price, feather meal is currently incorporated into animal feed as a protein source for farm species. Few data are available on residual drugs in feathers from treated animals. A depletion study was performed with laying hens treated intramuscularly with 5% enrofloxacin (Enromic) at 10 mg/kg body weight over 3 days. Thirty-three birds were treated and slaughtered at different times between 6 and 216 h after treatment; and samples of muscle plus skin, liver, kidney, and feathers were collected. High-performance liquid chromatography coupled with a tandem mass spectrometry method was validated before sample analysis to determine the decision limit, detection capability, recovery, and precision. Liver was the edible tissue with the slowest drug depletion. A withdrawal time of 6 days was calculated based on European Union maximum residual limits (100 microg/kg). A withdrawal time of 9 days was calculated based on Japan maximum residual limits (10 microg/kg). Enrofloxacin plus ciprofloxacin concentrations in feathers remained high through all sampling periods. Thus, feathers from treated animals should not be fed to food-producing animals.