Pharmacokinetics of cefquinome in red-eared slider turtles (Trachemys scripta elegans) after single intravenous and intramuscular injections

A pilot study on the pharmacokinetics of a single intramuscular injection of cefquinome in Arabian camel calves

This study was conducted to evaluate the pharmacokinetics of cefquinome in camel calves after a single intramuscular injection in a dose of 2 mg/kg body weight (kg b. w.). Cefquinome concentrations were measured by ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS). A non-compartmental pharmacokinetic model was used to fit the time-concentration curve and estimate the pharmacokinetic parameters. The peak serum concentration (Cmax) was 28.4 μg/mL at the time of maximum concentration (Tmax) of 25 min. The elimination half-life (t1/2) was 17.4 h. The area under the concentration-time curve (AUC0-∞) was 103.7 μg/ml-1h and the mean residence time (MRT0-∞) was 21.3 h. In comparison with other animal species, the pharmacokinetics of cefquinome in Arabian camel calves showed faster absorption from the site of injection and slower elimination. Since cefquinome, as other beta-lactams, is a time-dependent antimicrobial agent, a single dose of 2 mg/kg b. w. might be sufficient against the most sensitive organisms in camel calves owing to its prolonged elimination phase. However, dose readjustment is required for cases needing concentrations above 2 µg/mL for 12 h or above 1 µg/mL for 24 h.

Population pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin in clinically diseased or injured Eastern box turtles (Terrapene carolina carolina), yellow-bellied sliders (Trachemys scripta scripta), and river cooters (Pseudemys concinna)

Enrofloxacin is frequently administered to turtles in wildlife clinics during rehabilitation due to its wide spectrum of antibacterial activity and availability of injectable formulations. However, sufficient pharmacokinetic data to guide dosing are lacking. The objective of this study was to determine pharmacokinetic parameters of enrofloxacin and its active metabolite, ciprofloxacin, in chelonians presenting injured to a wildlife clinic. Thirty-six Eastern box turtles (EBT, Terrapene carolina carolina), 23 yellow-bellied sliders (YBS, Trachemys scripta scripta), and 13 river cooters (RC, Pseudemys concinna) received a single subcutaneous injection of enrofloxacin at 10 mg/kg. Blood samples were collected between 0 and 240 hr postinjection. Pharmacokinetic parameters were determined using nonlinear mixed-effects modeling (NMLE). Overall elimination half-life (T½) was over 75 hr, and varied among species. T½ was 63 hr in EBT and 79 hr in YBS, which is longer than in previous reports. The volume of distribution (steady-state) was 1.4 L/kg across turtle species, but highly variable-ranging from 0.4 L/kg in RC to 1.9 L/kg in YBS. Antibiotic concentrations were above a minimum inhibitory concentration value of 0.5 µg/ml for over 200 hr. These results indicate variable pharmacokinetic parameters for enrofloxacin among turtle species, which will help guide appropriate dosing protocols in injured turtles.

Pharmacokinetics of tolfenamic acid in red-eared slider turtles (Trachemys scripta elegans)

OBJECTIVE

To determine the pharmacokinetics of tolfenamic acid (TA) after different routes of administration [intravenous (IV) and intramuscular (IM), 2 mg kg^-1] and doses (IV, 2 and 4 mg kg^-1) in red-eared slider turtles (Trachemys scripta elegans).

STUDY DESIGN

Randomized experimental trial.

ANIMALS

Sixteen healthy red-eared slider turtles.

METHODS

Turtles were randomly assigned to two groups (n = 8 each). Group 1 received TA at a dose of 2 mg kg^-1 IV and then IM, after a washout period of 30 days. Group 2 received 4 mg kg^-1 TA IV. A noncompartmental analysis was used to calculate pharmacokinetic variables.

RESULTS

No local and/or systemic adverse drug effects were observed in any turtle. Elimination half-life and mean residence time following IM administration at 2 mg kg^-1 were significantly longer than those following IV administration. The bioavailability following IM administration was complete. The area under the plasma concentration-time curve, elimination half-life, mean residence time and total clearance were significantly different between the dose groups.

CONCLUSIONS AND CLINICAL RELEVANCE

The absence of adverse reactions in the turtles of the study of TA along with the favourable pharmacokinetic properties (the long half-life and the complete bioavailability) of TA administered at the single doses of 2 and 4 mg kg^-1 suggest the possibility of its effective use in turtles. However, further studies are required to establish a multiple dosage regimen of TA and to evaluate the clinical efficacy of administering TA.

Pharmacokinetics of ceftriaxone in Green sea turtles (Chelonia mydas) following intravenous and intramuscular administration at two dosages

Green sea turtles are widely distributed in tropical and subtropical waters. Adult green sea turtles face many threats, primarily from humans, including injuries from boat propellers, being caught in fishing nets, pollution, poaching, and infectious diseases. To the best of our knowledge, limited pharmacokinetic information to establish suitable therapeutic plans is available for green sea turtles. Therefore, the present study aimed to describe the pharmacokinetic characteristics of ceftriaxone (CEF) in green sea turtles, Chelonia mydas, following single intravenous and intramuscular administrations at two dosages of 10 and 25 mg/kg body weight (b.w.). Blood samples were collected at assigned times up to 96 hr. The plasma concentrations of CEF were measured by liquid chromatography tandem mass spectrometry. The concentrations of CEF in the plasma were quantified up to 24 and 48 hr after i.v. and i.m. administrations at dosages of 10 and 25 mg/kg b.w., respectively. The C_max values of CEF were 15.43 ± 3.71 μg/ml and 43.48 ± 4.29 μg/ml at dosages of 10 and 25 mg/kg, respectively. The AUC_last values increased in a dose-dependent fashion. The half-life values were 2.89 ± 0.41 hr and 5.96 ± 0.26 hr at dosages of 10 and 25 mg/kg b.w, respectively. The absolute i.m. bioavailability was 67% and 108%, and the binding percentage of CEF to plasma protein was ranged from 20% to 29% with an average of 24.6%. Based on the pharmacokinetic data, susceptibility break-point and PK-PD index (T > MIC, 0.2 μg/ml), i.m. administration of CEF at a dosage of 10 mg/kg b.w. might be appropriate for initiating treatment of susceptible bacterial infections in green sea turtles.