Penetration of oxytetracycline into the nasal secretions and relationship between nasal secretions and plasma oxytetracycline concentrations after oral and intramuscular administration in healthy pigs.

The penetration of oxytetracycline (OTC) in plasma and nasal secretions of healthy pigs was evaluated during the first study, in response to oral dose of 20 mg of OTC per kg of body weight (bwt) per day as a 400 mg/kg feed medication (n = 5) and to intramuscular (i.m.)-administered formulations at 10 mg/kg bwt (n = 5), 20 mg/kg bwt (n = 5), 40 mg/kg bwt (n = 5). Concentrations of OTC in plasma and nasal secretions were determined by a validated ultra-high performance liquid chromatography associated to tandem mass spectrometry method (UPLC/MS/MS). The objectives were to select the efficacy treatment and to evaluate the possibility to predict nasal secretions concentrations from those determined in plasma. The animals were housed together in each experiment. In each group, the treatment was administered once daily during 6 consecutive days, and nasal secretions and plasma were collected after 4 and 24 h at day 2 and day 6. For oral administration, only one medicated feed was prepared and distributed to all the animals together and was consumed in approximately 1 h. To meet recommendations of efficacy for OTC in nasal secretions, only the i.m. of 40 mg/kg bwt associated to an inter-dosing interval of 24 h provides and maintains concentrations in nasal secretions ≥1 μg/mL, appropriate to the MIC 50 and 90 of Pasteurella multocida and Bordetella bronchiseptica, respectively, the main pathological strains in nasal secretions. It has been demonstrated that, using a generalized linear mixed model (GLMM), OTC in the nasal secretions (μg/mL) can be predicted taking into account the OTC concentrations in plasma (μg/mL), according to the following equation: OTC(nasal secretions)  = 0.28 OTC(plasma) -1.49. In a second study, the pharmacokinetic behaviour of OTC in plasma and nasal secretions of healthy pigs was investigated, after single-dose i.m. of 40 mg/kg bwt of the drug. Blood samples and nasal secretions were collected at predetermined times after drug administration. The data collected in 10 pigs for OTC were subjected to non-compartmental analysis. In plasma, the maximum concentration of drug (C(max) ), the time at which this maximum concentration of drug (T(max) ) was reached, the elimination half-life (t½) and the area under the concentration vs. time curve (AUC) were, respectively, 19.4 μg/mL, 4.0, 5.1 h and 150 μg·h/mL. In nasal secretions, C(max) , T(max) , t½ and AUC were, respectively, 6.29 μg/mL, 4.0, 6.6 h and 51.1 μg·h/mL.

Bimazubute M ，Cambier C ，Baert K ，Vanbelle S ，Chiap P ，Gustin P ... -  《-》

Penetration of enrofloxacin into the nasal secretions and relationship between nasal secretions and plasma enrofloxacin concentrations after intramuscular administration in healthy pigs.

Bimazubute M ，Cambier C ，Baert K ，Vanbelle S ，Chiap P ，Albert A ，Delporte JP ，Gustin P ... -  《-》

Muscle tissue kinetics of oxytetracycline following intramuscular and oral administration at two dosages to giant freshwater shrimp (Macrobrachium rosenbergii).

Poapolathep A ，Poapolathep S ，Jermnak U ，Imsilp K ，Wannapat N ，Sugita-Konishi Y ，Kumagai S ... -  《-》

Plasma concentrations of oxytetracycline in swine after administration of the drug intramuscularly and orally in feed.

Hall WF ，Kniffen TS ，Bane DP ，Bevill RF ，Koritz GD ... -  《JAVMA-JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION》

Correlation between oral fluid and plasma oxytetracycline concentrations after intramuscular administration in pigs.

The penetration of oxytetracycline (OTC) into the oral fluid and plasma of pigs and correlation between oral fluid and plasma were evaluated after a single intramuscular (i.m.) dose of 20 mg/kg body weight of long-acting formulation. The OTC was detectable both in oral fluid and plasma from 1 hr up to 21 day after drug administration. The maximum concentrations (Cmax ) of drug with values of 4021 ± 836 ng/ml in oral fluid and 4447 ± 735 ng/ml in plasma were reached (Tmax ) at 2 and 1 hr after drug administration respectively. The area under concentration-time curve (AUC), mean residence time (MRT) and the elimination half-life (t1/2β ) were, respectively, 75613 ng × hr/ml, 62.8 hr and 117 hr in oral fluid and 115314 ng × hr/ml, 31.4 hr and 59.2 hr in plasma. The OTC concentrations were remained higher in plasma for 48 hr. After this time, OTC reached greater level in oral fluid. The strong correlation (r = .92) between oral fluid and plasma OTC concentrations was observed. Concentrations of OTC were within the therapeutic levels for most sensitive micro-organism in pigs (above MIC values) for 48 hr after drug administration, both in the plasma and in oral fluid.

Gajda A ，Jablonski A ，Gbylik-Sikorska M ，Posyniak A ... -  《-》