Pharmacokinetics of a single oral dose of acyclovir and valacyclovir in North American box turtles (Terrapenesp.)

Effect of benzylpenicillin on intravenous pharmacokinetics of acyclovir in red-eared slider turtles (Trachemys scripta elegans)

The aim of this study was to determine the effect of benzylpenicillin on the pharmacokinetics of acyclovir in red-eared slider turtles (Trachemys scripta elegans). Six clinically healthy red-eared slider turtles weighing 400 and 580 g were used for the study. Acyclovir (40 mg/kg) and benzylpenicillin (30 mg/kg) were administered intravenously to turtles. In the study, the cross-pharmacokinetic design (2 × 2) with a 30-day washout period was performed in two periods. Plasma concentrations of acyclovir were assayed using the high-performance liquid chromatography with fluorescence detection. Pharmacokinetic parameters were calculated by two-compartment open pharmacokinetic model. Following the administration of acyclovir alone, elimination half-life (t_{1/2 β} ), area under the plasma concentration-time curve (AUC), total clearance (Cl_T ), and volume of distribution at steady-state (V_dss ) were 20.12 hr, 1,372 hr * µg/mL, 0.03 L hr^-1  kg^-1 , and 0.84 L/kg, respectively. Benzylpenicillin administration increased t_{1/2 β} , AUC, and V_dss while decreased Cl_T of acyclovir. These results showed that benzylpenicillin changed the pharmacokinetics of acyclovir following simultaneous administration in turtles. However, further research is needed to determine molecular mechanism of interaction in turtle.

In vitro and in vivo assessment of eprociclovir as antiviral treatment against testudinid herpesvirus 3 in Hermann's tortoise (Testudo hermanni)

Tortoises belonging to the Testudinidae family are infected by Testudinid herpesviruses. Testudinid herpesvirus 3 (TeHV-3) is considered the most pathogenic and affects several tortoise species, particularly those from the Testudo genus. As most species of this genus are endangered contribute to ecological concerns over this virus. Here, we aimed to explore the rational development of an antiviral treatment against TeHV-3 using Hermann's tortoise (Testudo hermanni) as a host model. Ten antiviral compounds were tested in cell culture for their toxicity and their activity against TeHV-3. Eight compounds exhibited different levels of activity against TeHV-3 with either no or only minor cytotoxic effects on cells. Next, eprociclovir (EPV, ciprovir) was selected for further investigations in vivo. Its pharmacokinetic properties were investigated after a single sub-cutaneous administration at 5 or 10 mg/kg. Plasma concentrations remained above half maximal effective concentration (EC₅₀) for 2.2 and 4.4 h after administration at 5 and 10 mg/kg, respectively. Finally, EPV toxicity was investigated after administration at the dose of 10 mg/kg, BID for seven consecutive days. As early as one day after initiation of the treatment up to its end, EPV plasma concentration remained under the EC_50. Apathy and anorexia developed after 7 days. Biochemical and anatomopathological examinations revealed nephrotoxic effects of EPV. Altogether, these data suggest that EPV is not a suitable molecule for the treatment of TeHV-3. Further studies are required to determine whether the other molecules identified here for their anti-TeHV-3 activity represent potential candidates for the development of efficacious treatments.