AN ASSAY FOR FURAZOLIDONE RESIDUES BY LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION APPLICABLE TO DEPLETION STUDIES IN PIGS

A liquid chromatographic method with electrochemical detection in the reduction mode has been adapted for the estimation of furazolidone in pig tissues at residue levels. Chromatography of standard solutions shows good linearity from 0.2 to at least 10 ng injected. The limit of quantitation in spiked blank muscle and plasma is 0.5 ppb with 70% recovery and coefficients of variation ranging from 3.7 to 8.7%. In plasma, the concentration remains unchanged for up to 4 weeks at -30 °C, but the drug disappears rapidly from muscle both at room temperature and at -30 °C. Heat inactivation of spiked muscle by microwave increases the stability on storage. After the medicated diet is fed to pigs (330 ppm), the drug accumulates rapidly in plasma, reaching steady-state concentrations of approximately 500 ppb within 1/2h, but drops overnight to below the limit of detection (0.2 ppb). The concentration in the muscle is about 3-6 times lower than in plasma. Depletion from both tissues occurs with a half-life of approximately 2 h. Furazolidone is not detected in liver and kidney at any time. © 1990, American Chemical Society. All rights reserved.