Pharmacokinetics of ponazuril after administration of a single oral dose to green turtles (Chelonia mydas)

Abstract

The coccidian protozoan, Caryospora cheloniae , has been associated with severe enteritis and encephalitis in immature farm-raised green turtles ( Chelonia mydas ) in the Cayman Islands, immature green turtles off the coast of Florida, and immature stranded sea turtles in Australia. An effective anti-coccidial drug that is both orally absorbed and well-distributed throughout the body is needed for treatment of turtles diagnosed with coccidiosis in rehabilitation facilities. Ponazuril is a triazine antiprotozoal drug that is approved in the USA for the treatment of another Apicomplexan, Sarcocystis neurona, and has also been successfully used in the therapy of other coccidian parasites. The objective of this study was to perform an oral dose-ranging pilot study (10–100 mg/kg of body weight ponazuril) in green turtles (N = 9), followed by oral administration of ponazuril at 100 mg/kg body weight (N = 8) to assess its disposition. Another goal of this study was to optimize the method of oral drug administration to green turtles. Plasma ponazuril concentrations were quantified using high performance liquid chromatography (HPLC). Standard compartmental models were fit to the data. Ponazuril was absorbed after oral administration at 100 mg/kg BW, with a maximum plasma concentration of 3.3 µg/ml. Dose-dependent pharmacokinetic parameters only weakly correlated with the dose rate, apparently due to considerable pharmacokinetic variability observed between turtles. Administration of ponazuril in gelatin capsules using a balling gun was deemed the least variable and most successful method of drug administration. Further studies are needed to evaluate the safety and efficacy of ponazuril in sea turtles with coccidiosis.

Systemic Caryospora-like coccidiosis in a clutch of hatchling red-eared slider turtles (Trachemys scripta elegans)

“…Several treatments have been attempted in CLO-infected marine turtles including supportive care and the use of triazine anti-coccidials (ponazuril or toltrazuril), 17,30 a group of anti-coccidials that are thought to target the apicoplast, and/or metronidazole. 24 Importantly, triazine treatments are reportedly effective at blocking intracellular propagation of the zoites, improving clinical disease.…”

“…However, fibrinonecrotic enterocolitis and necrotizing hepatitis were not a feature in those cases, and the molecular characterization in those turtles revealed coinfections with 2 different Eimeria species. 14 Several treatments have been attempted in CLO-infected marine turtles including supportive care and the use of triazine anti-coccidials (ponazuril or toltrazuril), 17,30 a group of anticoccidials that are thought to target the apicoplast, and/or metronidazole. 24 Importantly, triazine treatments are reportedly effective at blocking intracellular propagation of the zoites, improving clinical disease.…”

Pharmacokinetics, bioavailability, and excretion of ponazuril in piglets

“…Currently, the pharmacokinetics of ponazuril has been reported in a variety of animals including cattle ( 23 ), goats ( 24 ), camels ( 25 ), cats ( 26 ), horses ( 27 ), turtles ( 28 ), and weaned pigs ( 29 ). But no relevant studies targeting ponazuril in piglets aged 0–4 weeks, which is the optimal administration time to control coccidiosis, have been published thus far.…”