The therapy database currently used in elasmobranchs is still mostly based on empirical data, and there are few efficacy and safety studies supporting clinical practice. In this study, meloxicam pharmacokinetics (PK) were evaluated after a single 1.5 mg/kg IM administration to a group of seven clinically healthy adult undulate skates (Raja undulata Lacepède, 1802). Blood samples were collected before administration and at 15, 30, 60 and 90 min and 2, 4, 8, 12, 24 and 48 h after the IM injection. The meloxicam concentrations in plasma were determined using high-performance liquid chromatography, and PK parameters were calculated using a non-compartmental model approach. The mean ± SEM values of the main PK values were 1.84 ± 0.31 μg/mL for peak plasma concentration, 1.5 ± 0.24 h for time to maximum plasma concentration, 11.43 ± 2.04 h·µg/mL for area under the plasma concentration vs. time curve, 3.55 ± 0.65 h for elimination half-life, and 5.37 ± 0.94 h for mean residency time. No adverse reactions were detected. The relatively high plasma concentration and short time to maximum plasma concentration suggest that meloxicam could turn into an efficient analgesic and anti-inflammatory candidate drug to be used in skates. Further efficacy, pharmacodynamic, and multiple-dose studies with meloxicam are needed in elasmobranchs.

Introduction: Elasmobranchs currently constitute an important part of the animal collection of many aquariums worldwide. Their maintenance under human care has allowed us to describe and identify new pathogens and diseases affecting them, as well as to determine different treatments for these diseases. Great advances in elasmobranch husbandry have been developed. Methods: A search was performed on scientific databases as PubMed and other specialized sources (IAAAM archive). Results: Little information on pharmacotherapeutics is available in this taxonomic group, and treatments lack a scientific base and instead are frequently dependent on empirical knowledge. Pharmacokinetic studies are the first step to determining therapeutic protocols that are safe and effective. The available bibliography shows that a majority of the mycoses recorded in cartilaginous fish are severe, aggravated by the fact that the antifungal treatments administered, following the guidelines used for teleost species, are ineffective in elasmobranchs. Azoles appear to be a promising group of antifungals for use in treating systemic mycoses in sharks and rays. Conclusions: Based on the findings of this review, it is essential to investigate the pharmacokinetics of the different antifungals in these species in order to provide therapeutic options for fungal infections in cartilaginous fish.

Fungal diseases, despite their low incidence in sharks and rays, are considered emerging diseases in this group of animals and can lead to high mortality rates despite treatment. The information available related to the treatment of fungal diseases in elasmobranchs is limited and is frequently based on the empirical knowledge provided by the professionals and clinicians working with these species. The use of azole antifungal drugs, especially voriconazole, has shown promise as a potential treatment option for fungal infections in elasmobranchs, with favorable outcomes in some registered cases. However, scientific knowledge regarding azole pharmacokinetics (PK) in fish remains limited, and despite the recent publication of a PK study with voriconazole in rays, there are still no published PK studies for azoles in sharks. In this study, voriconazole was administered at 4 mg/kg intravenously (IV) and intramuscularly (IM) to nursehound sharks (Scyliorhinus stellaris) (n = 6). Blood samples were collected before administration and at nine predetermined time intervals afterwards (0.25, 0.5, 1, 1.5, 2, 4,8,12, 24, and 36 h). Plasma concentrations were determined using a validated high-performance liquid chromatography (HPLC) method, and pharmacokinetic (PK) parameters were estimated using a non-compartmental model. The mean peak plasma concentrations (C_max) ± SEM after IM administration was 3.00 ± 0.23 µg/mL. The volume of distribution (Vd) after IV and IM administration resulted in 1.39 ± 0.09 L/kg and 1.50 ± 0.18 L/kg, respectively, showing no statistically significant differences between the two routes. Clearance (Cl) values were 0.12 ± 0.01 mL/min after IV administration and 0.29 ± 0.05 mL/min after IM administration. No adverse effects were detected during the study or four weeks after administration. These results support the administration of IV and IM voriconazole in sharks; however, additional studies on toxicity and pharmacodynamics are necessary. Moreover, further research on the susceptibility of fungal pathogens affecting elasmobranchs is needed to establish an optimal dosing regimen for IM voriconazole in the treatment of mycosis in sharks.

Fungal diseases represent an ongoing problem for elasmobranchs kept under human care worldwide. When present, mycoses often lead to high mortality rates, compromising welfare and conservation programs in aquariums. Various fungal species have been identified as causative agents, with Fusarium solani complex most frequently being isolated. Treatment remains unclear; however, recent clinical reports have shown positive outcomes after the administration of azole antifungal drugs to elasmobranchs affected by different fungal infections, specifically for voriconazole. Clinical cases report different dose regimens and administration routes, and pharmacokinetic (PK) studies in elasmobranchs are needed. For this purpose, a PK study was performed and voriconazole was administered at 50 mg/kg PO to six nursehound sharks (Scyliorhinus stellaris) and six undulate skates (Raja undulata). Plasma concentrations were determined using a validated high-performance liquid chromatography (HPLC) method, and PK parameters were estimated using a non-compartmental model. The mean peak plasma concentration (Cmax) ± standard error of the mean (SEM) after oral administration of 50 mg/kg of voriconazole was 3.32 ± 0.92 µg/ml in nursehound sharks and 10.53 ± 0.91 µg/ml in undulate skates. Terminal-half lives for sharks and skates resulted 113.43 ± 29.45 h and 9.88 ± 1.33 h, respectively. Plasma concentrations were above MIC50 in vitro values for Fusarium solani for 54 to 72 h. These findings suggest that voriconazole persists longer in sharks due to extended half-life, whereas in skates, the drug reaches higher plasma concentrations but is eliminated more rapidly. These interspecies variations should be considered when selecting the oral administration route for treatment and determining the appropriate posology regimens for antifungal therapy in elasmobranchs.

There is an error in the reference order in the original publication