Los animales fueron sacrificados de a pares, a las 24, 48, 96, 144 y 192 horas posteriores a la última administración. Muestras de tejido (incluyendo grasa, músculo, hígado y riñón) y plasma se recogieron luego de la muerte de cada cerdo.

Las concentraciones de NN fueron determinadas por cromatografía líquida de alta performance con detector UV.

Los resultados demostraron buena absorción gastrointestinal de NN, con corta persistencia en plasma y grasa, intermedia en músculo y prolongada en hígado y riñón, lo cual debería considerarse para determinar tiempos de retirada para consumo en esta especie doméstica.

SUMMARY: Norfloxacin nicotinate (NN) is a fluoroquinolone antibacterial agent with a high antimicrobial activity against a very wide range of gram negative and a number of gram positive aerobes as well as most pathogenic mycoplasmas.

Tissular and blood concentrations of a comercial preparation of NN (Vetantril-N", Vetanco) in pigs after oral administration were determined. The drug was diluted in distilled water and administered to ten healthy male pigs through a naso-esophagic tube at a daily dose of 18 mg/kg by five consecutive days. To adjust the dose each individual was weighed out before every administration.

Animals were sacrificed in pairs at 24, 48, 96, 144 and 192 hours after last administration. Tissular (included fat, muscle, liver and kidney) and plasma samples were collected from each pig.

NN concentrations were determined by high performance liquid chromatography using UV detection.

Results demonstrate good NN gastrointestinal absorption, with shorter persistance in plasma and fat, intermediate persistance in muscle and longer in liver and kidney, which should be taken into account when determining withdrawal times on this domestic specie.

Palabras claves: porcinos, norfloxacina, residuos.
Key words: pigs, norfloxacin, residues.