Determination of tilmicosin in swine feeds by liquid chromatography

• Published in: Journal of AOAC International Vol. 80; no. 6; p. 1161
• Main Authors: Readnour, R.S, Helton-Groce, S.L, Dixon, S.S
• Format: Journal Article
• Language: English
• Published: England 01.11.1997
• Subjects: ALIMENT MEDICAMENTEUX POUR ANIMAUX; ANALISIS CUANTITATIVO; ANALYSE QUANTITATIVE; Animal Feed; Animals; Anti-Bacterial Agents - analysis; ANTIBIOTICOS; ANTIBIOTICS; ANTIBIOTIQUE; CHROMATOGRAPHIE; CHROMATOGRAPHY; Chromatography, Liquid; CROMATOGRAFIA; Food Contamination; Linear Models; MACROLIDE ANTIBIOTICS; Macrolides; MEASUREMENT; MEDICATED FEED; MEDICION; MESURE; PIENSOS MEDICINALES; Quality Control; QUANTITATIVE ANALYSIS; Reproducibility of Results; Sensitivity and Specificity; Swine; Tylosin - analogs & derivatives; Tylosin - analysis
• ISSN: 1060-3271; 1944-7922
• DOI: 10.1093/jaoac/80.6.1161

This method determines tilmicosin in feeds over a concentration range of 100 to 600 mg/kg. Tilmicosin is extracted from swine feeds by adding 200 ml of a swine feed extractant (20 + 80, acetonitrile-Millipore water, pH 2.5, with 25 mM dibutylammonium phosphate) to 20 g feed and placing on a shaker table for 1 h. This extractant is filtered and analyzed by liquid chromatography (LC). A gradient LC method is used to separate tilmicosin from the feed matrix in 30 min of run time. The recovery of tilmicosin from fortified feeds ranged from 96.7 to 112%, with the coefficients of variation (CVs) ranging from 1.4 to 3.9%. The determination of tilmicosin in medicated feeds resulted in an average recovery of 92.7% of labeled claim for pelleted feeds at 200 mg/kg and 99.1% of labeled claim for mash feeds at 400 mg/kg. Determination of tilmicosin in medicated feeds resulted in CVs ranging from 2.6 to 3.8%. The method has shown no interference with 18 other drugs