Study on the pharmacokinetics of enrofloxacin in the Chinese mitten-handed crab,Eriocheir sinensis, after different administration regimes

Abstract

A pharmacokinetic study on enrofloxacin (ENR) following different administration regimes (i.e. intramuscular, oral and bath administrations) was carried out for the Chinese mitten-handed crab (Eriocheir sinensis) at 17 °C water temperature. Muscle and hepatopancreas samples were collected at each sampling time of 1 and 10 min and 0.5, 1, 2, 8, 16, 24, 48, 72 and 168 h for intramuscular administration and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 48, 72 and 168 h for oral and bath administration. The levels of ENR and ciprofloxacin (CIP) were simultaneously determined (n=5) by high-performance liquid chromatography. The results showed that similar absorption and elimination patterns of ENR level in muscle and hepatopancreas were observed for oral administration and bath treatment; however, the trend in ENR level changes in muscle and hepatopancreas after intramuscular administration was quite different from oral and bath treatments. Meanwhile, the level of ENR in hepatopancreas was much higher than that in muscle for the same administration regimes. The concentration–time data were analysed with the Practical Pharmacokinetics Program (3P97), and the kinetic profiles of ENR in the hepatopancreas and muscle conformed to two-compartment models. The absorption and elimination of ENR in hepatopancreas for bath treatment were faster than those for oral and intramuscular administrations. However, the pattern was quite different in muscle. The fastest absorption and elimination of ENR in muscle were seen for intramuscular administration.