Evaluation of an extended-release formulation of ceftiofur crystalline-free acid in koi (Cyprinus carpio)

PHARMACOKINETICS OF SINGLE INTRAMUSCULAR ADMINISTRATION OF CEFTIOFUR CRYSTALLINE FREE ACID IN AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS)

A pharmacokinetic study of ceftiofur crystalline free acid sterile oil suspension (CCFA) was performed in six apparently healthy juvenile American alligators (Alligator mississippiensis). A single intramuscular dose of 30 mg/kg was administered in the triceps muscle. Blood samples were collected prior to treatment and at 4, 12, 24, 48, 72, 120, 144, 192, 288, and 366 h post administration. Plasma samples were analyzed for ceftiofur equivalent concentrations using liquid chromatography-mass spectrometry. Pharmacokinetic parameters were determined by noncompartmental analysis. Mean peak plasma concentration was 23.2 µg/ml (range, 16.0-27.9), median time to maximum concentration was 72 h (range, 72-120), mean area under the curve from 0 to 366 h postdose was 4.24 h · mg/ml (range, 3.54-4.97), and mean terminal half-life was 143 h (range, 90.8-220). Plasma concentrations were maintained above the minimum inhibitory concentration for this study of 2.0 µg/ml, which was established from similar CCFA pharmacokinetic studies in other reptilian species, through the end of the data collection of 366 h. Because of prolonged plasma concentrations, a dosing interval could not be established in this study. Future studies should include extended collection time points and multidose studies to determine dosing regimens.

PHARMACOKINETICS OF CEFTIOFUR CRYSTALLINE-FREE ACID ADMINISTERED VIA INTRAMUSCULAR INJECTION IN WHOOPING CRANES (GRUS AMERICANA)

The objective of this study was to evaluate the pharmacokinetic properties of a single dose of ceftiofur crystalline-free acid (CCFA) in whooping cranes (Grus americana). Ceftiofur crystalline-free acid is a long-acting, injectable, third-generation cephalosporin antibiotic drug. A preliminary study evaluated CCFA administered intramuscularly in the pectoral or thigh muscle at 20 or 30 mg/kg IM to a single adult whooping crane for each dose. On the basis of these data, a dose of 30 mg/kg IM of CCFA was administered to five additional whooping cranes, and blood was collected at various time points from 0 to 288 h. Pharmacokinetic parameters for ceftiofur equivalents were determined and reached concentrations above minimum inhibitory concentrations of various bacteria in other avian species (>1 µg/ml) for at least 96 h in all birds, and for 144 h in two birds. From these findings, ceftiofur crystalline-free acid appears to be a long-acting antibiotic option for whooping cranes and may be dosed every 96 h; however, additional multidose studies are needed.

PHARMACOKINETIC, PHARMACODYNAMIC, AND TOXICOLOGY STUDY OF ROBENACOXIB IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

Postoperative antinociception control in fish is currently suboptimal, as commonly used antiinflammatory drugs last for only a few hours at tested temperatures. Therefore, long-acting anti-inflammatory drugs, such as robenacoxib, could improve the welfare of fish. The pharmacokinetics, duration of antinociceptive action, and potential adverse effects of robenacoxib were evaluated through two prospective randomized blinded trials in rainbow trout (Oncorhynchus mykiss). Six healthy rainbow trout received a single IM administration of robenacoxib (2 mg/kg), and two control fish received the same volume of saline IM. Blood samples were collected at predetermined time points for 5 d. Plasma robenacoxib concentrations were measured using high-performance liquid chromatography-high-resolution hybrid orbitrap mass spectrometry and noncompartmental pharmacokinetic analysis. Ten additional rainbow trout received an intralabial injection of 0.05 ml of 2% acetic acid following a previously validated nociceptive model. The treated group (n = 6) received 2 mg/kg of robenacoxib IM and the control group (n = 4) received an equivalent volume of saline IM. The behavior, appetite, and opercular rate of the fish were evaluated every hour for 5 h, then once daily for 3 d. All 12 treated trout and 6 controls underwent histopathologic evaluation. Average maximum plasma concentration (C_max) was 329.9 ± 137.3 ng/ml observed at 2.1 ± 0.7 h (T_max) and terminal half-life was 12.6 ± 2.27 h. Plasma concentrations described as antinociceptive in domestic carnivores were measured for 3-4 d. This dose was associated with a significant decrease in rocking behavior (P = 0.017). No adverse effects were detected clinically nor on histopathology. Robenacoxib administered IM at 2 mg/kg appears to be safe and may provide an antinociceptive effect in rainbow trout. This study presents a new therapeutic option to provide long-lasting antinociception in rainbow trout.

PHARMACOKINETICS AND CLINICAL SAFETY OF A SUSTAINED-RELEASE FORMULATION OF CEFTIOFUR CRYSTALLINE FREE ACID IN RINGNECK DOVES (STREPTOPELIA RISORIA) AFTER A SINGLE INTRAMUSCULAR INJECTION

Ceftiofur crystalline free acid (CCFA) is a third-generation, oil-based, cephalosporin antimicrobial marketed as a once weekly treatment in cattle and swine, and as a two-time dose with 10-day duration in horses. Because handling and restraint times can be reduced, long-acting antibiotic preparations are particularly useful for treatment of nondomestic species. This study evaluated the pharmacokinetics of CCFA in ringneck doves (Streptopelia risoria). A single intramuscular (IM) injection of CCFA at 50 mg/kg was administered to each of 30 doves, and blood was collected from subsamples of 6 birds at predetermined sampling times (i.e., with a postinjection range of 0.5 to 192 hr). All ringneck doves were scheduled for euthanasia because of reasons unrelated to the study; this was performed at the conclusion of the study; and complete postmortem and histopathologic examinations were performed. Plasma concentrations of CCFA remained above the minimum inhibitory concentration (1.0 µg/ml; observed for most avian pathogenic bacteria) for 108 hr. No abnormalities were identified on individual birds before and after clinical pathology results (i.e., hematocrits and plasma biochemistry profiles), and only minimal gross and histopathologic changes such as mild tissue inflammation at the injection site were observed. Based on these results, one IM injection of CCFA at 50 mg/kg seems to be a potential option for treatment of ringneck doves.

Overview of Drug Delivery Methods in Exotics, Including Their Anatomic and Physiologic Considerations

Drug delivery to exotic animals may be extrapolated from domestic animals, but some physiologic and anatomic differences complicate treatment administration. Knowing these differences enables one to choose optimal routes for drug delivery. This review provides practitioners with a detailed review of the currently reported methods used for drug delivery of various medications in the most common exotic animal species. Exotic animal peculiarities that are relevant for drug administration are discussed in the text and outlined in tables and boxes to help the reader easily find targeted information.

Evidence-Based Advances in Aquatic Animal Medicine

Fish and aquatic invertebrates deserve evidence-based medicine. Pharmacologic information is available; most pharmacokinetic studies are derived from the aquaculture industry and extrapolated to ornamental fish. Conversely, advanced diagnostics and information regarding diseases affecting only ornamental fish and invertebrates require more peer-reviewed experimental studies; the examples of carp edema virus, sea star wasting disease, seahorse nutrition, and gas bubble disease of fish under human care are discussed. Antinociception is also a controversial topic of growing interest in aquatic animal medicine. This article summarizes information regarding new topics of interest in companion fish and invertebrates and highlights some future avenues for research.

Ceftiofur pharmacokinetics in Nile tilapia Oreochromis niloticus after intracardiac and intramuscular administrations

Ceftiofur is a broad-spectrum third generation cephalosporin, which acts by inhibiting bacterial cell wall synthesis. It is active against Gram-positive and Gram-negative bacteria such as Aeromonas hydrophila and β-lactamase-producing strains, which are common pathogens in freshwater fish. Ceftiofur pharmacokinetics in Nile tilapia Oreochromis niloticus were studied following single intracardiac (i.c.) or intramuscular (i.m.) administration of ceftiofur sodium (NAXCEL®) in a dose of 5 mg ceftiofur kg-1 body weight. After i.c. injection, ceftiofur plasma concentrations decreased biexponentially, suggesting a 2-compartmental open model. Distribution and elimination half-lives (t0.5(α) and t0.5(β)) were 0.61 ± 0.22 and 0.14 ± 0.03 h mean ±SD, respectively. Elimination constant (Kel) and total body clearances (Cltot) were 3.22 ± 0.48 h-1 and 1.64 ± 0.47 l h-1 kg-1, respectively. Volume of distribution (Vss) and areas under curves (AUC) were 0.12 ± 0.03 l kg-1 and 24.18 ± 8.81 µg ml-1 h, respectively. Following i.m. injection of ceftiofur, plasma concentrations were best described by a 1-compartment open model with a first order absorption; bioavailability was quite high (96.85 ± 23.74%). Plasma maximum concentration (Cmax) was 12.32 ± 6.53 µg ml-1; achieved at time of maximum concentration (Tmax) of 0.74 ± 0.04 h. Absorption and elimination half-lives (t0.5ab and t0.5β) were 0.49 ± 0.06 and 0.53 ± 0.03 h, respectively. In conclusion, i.m. injection of ceftiofur sodium produced extremely high bioavailability with high plasma concentrations that persisted up to 6 h post injection, which may make ceftiofur a useful alternative antibiotic for treatment of brood stock or important ornamental fishes.