Variation in water disappearance, daily dose, and synovial fluid concentrations of tylvalosin and 3‐O‐acetyltylosin in commerical pigs during five day water medication with tylvalosin under field conditions

Abstract

Tylvalosin (TVN) is a water soluble macrolide used in swine production to treat enteric, respiratory, and arthritic pathogens. There is limited data on its distribution to synovial fluid beyond gavage studies, which do not represent field conditions. This study measured water disappearance, TVN concentration in the medicated water, daily dose, and concentrations of TVN and 3-O-acetyltylosin (3AT) in the synovial fluid and plasma of treated pigs over the administration period. The study emphasized understanding variation in tissue TVN concentrations within the context of a field setting. Sixty finisher pigs were housed individually with individual waterers. Six pigs were randomly allocated to the following time points for sample collection: 0, 48, 60, 72, 84, 96, 102, 108, 114, and 120 hr on medication. TVN was administered daily in the water for 5 days. Water disappearance and medicated water concentration were measured daily. At each time point, six pigs were euthanized and plasma and synovial fluid were collected for analysis. Median TVN synovial fluid concentrations ranged between <1 ng/ml (hour 0) to 3.6 ng/ml (hour 84). There was substantial variation between individual pigs for water disappearance (mean 4.36L and range 0-7.84). Median TVN water concentration was 59 ppm (range 38-75 ppm).

Quantification and Determination of Stability of Tylvalosin in Pig Plasma by Ultra-High Liquid Chromatography with Ultraviolet Detection

“…An analytical method of validation to quantify tylvalosin (TV) in pig plasma by liquid chromatography (LC) with an ultraviolet detector has not yet been published. Only three methods have been reported to quantify TV in plasma, one of them using HPLC/MS [ 14 ] and the others using high-performance liquid chromatography with ultraviolet detection (HPLC/UV) (turkey plasma and chicken serum) [ 4 , 15 ]. Differences have been reported among different species in terms of the composition and functional properties of blood.…”

“…This result is similar to those obtained by other authors from avian plasma samples of 0.1 and 0.039 µg/mL [ 4 , 15 ]. A lower LOQ (0.001 µg/mL) was obtained in pig plasma [ 14 ] when TV was quantified by liquid chromatography–mass spectrometry (LC/MS) with solid-phase extraction (SPE). It must be admitted that high-performance liquid chromatography–mass spectrometry (HPLC/MS) methods have higher sensitivity than HPLC-UV and high-performance liquid chromatography with fluorescence detection (HPLC-FL) methods, but SPE, commonly used in mass spectrometry, results in longer analytical times per sample compared with the presented HPLC/UV method with protein precipitation.…”

“…Nowadays, only three methods can be found in the literature to determinate TV in plasma by HPLC. One of these methods quantifies the concentrations of this macrolide by liquid chromatography–mass spectrometry (LC/MS) in pig plasma with a quantification limit (LOQ) of 0.001 µg/mL [ 14 ]; the other two methods use high-performance liquid chromatography with ultraviolet detection (HPLC/UV) in turkey plasma and chicken serum [ 4 , 15 ] with an LOQ of 0.1 and 0.039 µg/mL, respectively. LC/MS methods show high sensitivity but unfortunately suffer from a high matrix effect (especially in mode: electrospray ionization), and these devices are not usually present in most clinical laboratories [ 16 , 17 , 18 ].…”

“…Regarding sample preparation, different methods have been used, such as solid-phase extraction (SPE) [ 14 ] and liquid–liquid extraction (LLE) [ 4 , 15 ]. Solid-phase extraction is widely used in liquid chromatography (LC) as high recoveries and good chromatograms are obtained, but it takes longer to perform and requires more steps [ 19 , 20 , 21 ].…”

In-Water Antibiotic Dosing Practices on Pig Farms

“…While the solubility thresholds of commonly used antibiotics are not exceeded when solutions are prepared for dosing using header tanks, some variation in the concentration of an antibiotic held in a header tank may occur over time if the solution is not continuously agitated [26]. The three farm managers using header tanks who dosed with each tank's inlet valve left open would be very unlikely to achieve PK/PD targets, as this practice results in a progressive dilution over the dosing period and thus a decline in the concentration of the antibiotic in the water supplied to the pigs.…”