PHARMACOKINETICS OF CEFTAZIDIME IN SIGNAL CRAYFISH (PACIFASTACUS LENIUSCULUS) FOLLOWING A SINGLE DOSE

Crustaceans are housed in zoos and aquariums and have also gained importance in the private sector and food industry. Shell lesions are common and often attributed to bacterial infections. However, few controlled studies have been performed evaluating antibiotics in crustaceans. This study assessed the pharmacokinetics of a single dose of ceftazidime (22 mg/kg) given by IM or IV injection in wild-caught signal crayfish (<i>Pacifastacus leniusculus</i>). Pharmacokinetic parameters were calculated by noncompartmental analysis of sparse data. Maximum ceftazidime hemolymph concentration following IM administration was 124.6 ± 14.7 µg/mL and Tmax was 5 min, with 80% bioavailability. Following IV administration, the extrapolated maximum concentration of ceftazidime, (C [0]), was 581.4 µg/mL. Ceftazidime was last detected at 72 hr and 120 hr post IM and IV administration, respectively. Terminal half-life was 8.03 hr and 10.3 hr after IM and IV administration, respectively. Results suggest that both routes have the capacity to reach a maximum hemolymph concentration quickly in signal crayfish. Moreover, ceftazidime was maintained above a concentration of 4 µg/mL, a published minimal inhibitory concentration for <i>Vibrio</i> spp., for 24 hr for both IM and IV routes. Therefore, ceftazidime may be useful for infections with susceptible <i>Vibrio</i> spp. in signal crayfish.