Pharmacokinetics of Ceftazidime After a Single Intramuscular Dose in Whitespotted Bamboo Sharks ( <i>Chiloscyllium plagiosum</i> )

Whitespotted bamboo sharks (Chiloscyllium plagiosum) are a common species of elasmobranchs housed in zoos and aquaria. Medical concerns like conspecific trauma and bacterial infections commonly lead to the empirical use of antibiotic medications like ceftazidime, despite limited pharmacokinetic studies in elasmobranchs. In this study, 36 whitespotted bamboo sharks were divided into six groups using a population pharmacokinetic design. They were administered a single intramuscular injection of ceftazidime at 20 mg/kg. Blood samples were collected for plasma drug concentration at time points T = 0 and 30 min, and 1, 2, 4, 6, 12, 24, 48, 72, and 96 h post-injection. Samples were analyzed by the Clinical Pharmacology Laboratory in the College of Veterinary Medicine of North Carolina State University using high-pressure liquid chromatography (HPLC) analysis. For at least 96 h, all sharks in the study maintained plasma concentrations of ceftazidime above the MIC of 4 μg/mL, which is considered susceptible when testing isolates from other animals. The long elimination half-time of 84.15 h suggests that recommended dosing intervals may be extended beyond the commonly used 3 days to at least every 96 h.