Pharmacokinetic profiles of amoxicillin trihydrate in freshwater crocodiles (Crocodylus siamensis) after intramuscular administration at two doses

Abstract

The aim of the present study was to elucidate the pharmacokinetic profiles of amoxicillin trihydrate (AMX) in Siamese freshwater crocodiles (Crocodylus siamensis). Crocodiles were administered a single intramuscular injection of AMX, at a dose of either 5 or 10 mg/kg body weight (b.w.). Blood samples were collected at preassigned times up to 120 hr. The plasma concentrations of AMX were measured using a validated liquid chromatography tandem‐mass spectrometry method. AMX plasma concentrations were quantifiable for up to 72 hr (5 mg/kg b.w.) and 96 hr (10 mg/kg b.w.). The elimination half‐life (t1/2λz) of AMX following dosing at 5 mg/kg b.w. (8.72 ± 0.61 hr) was almost identical to that following administration at 10 mg/kg b.w (8.98 ± 1.13 hr). The maximum concentration and area under the curve from zero to the last values of AMX increased in a dose‐dependent fashion. The average binding percentage of AMX to plasma protein was 21.24%. Based on the pharmacokinetic data, susceptibility break point, and the surrogate PK‐PD index (T > MIC, 0.25 μg/ml), intramuscular administration of AMX at dose of 5 mg/kg b.w. every 4 days might be appropriate for the treatment of susceptible bacterial infections in freshwater crocodiles.

Pharmacokinetic characteristics of azithromycin in freshwater crocodiles (Crocodylus siamensis) after intramuscular administration at three different dosages

“…The pharmacokinetic characteristics of some antimicrobial drugs such as enrofloxacin, tetracycline have been investigated in American alligators (Helmick et al, 2004; Rivera et al, 2012) while enrofloxacin has been investigated in estuarine crocodiles (Martelli et al, 2009). On the contrary, pharmacokinetic profiles of marbofloxacin, enrofloxacin, ceftriaxone, amoxicillin, oxytetracycline, and clarithromycin have been determined infreshwater crocodiles (Poapolathep et al, 2017; Poapolathep et al, 2022; Poapolathep, Giorgi, Chaiyabutr, Chokecharoenrat, et al, 2020; Poapolathep, Giorgi, Chaiyabutr, Klangkaew, et al, 2020; Poapolathep, Giorgi, Klangkaew, Phaochoosak, et al, 2020; Poapolathep, Klangkaew, Phaochoosak, Wongwaipirote, et al, 2020); however, there are no reports on the pharmacokinetics of AZM in freshwater crocodiles.…”

Pharmacokinetics of a Long-Acting Formulation of Oxytetracycline in Freshwater Crocodiles (Crocodylus siamensis) after Intramuscular Administration at Three Different Dosages

“…in the freshwater crocodile, C. siamensis. A few published papers have described the pharmacokinetics of antibacterial drugs in reptilian species-namely, American alligators, estuarine crocodiles and freshwater crocodiles [5][6][7][8][9][10][11]. However, to date, there have been no reports on the pharmacokinetics of OTC in the freshwater crocodile, C. siamensis.…”

“…Currently, there are few reports on the pharmacokinetics and dosage regimen of antimicrobial drugs in crocodiles. Regarding pharmacokinetic profiles, a number of antimicrobial drugs have been investigated in American alligators, estuarine crocodiles and freshwater crocodiles [5][6][7][8][9][10][11].…”

Veterinary pharmacology: A world almost unexplored with huge potential

“…Thus, the support of independent scientists results of paramount importance in order to expand the knowledges even in niche areas of the veterinary field. Recent examples of that have been reported in geese ( Sartini et al., 2020a , 2020 b , 2021a ,2021 b , 2021 c , 2022b ) and crocodiles ( Poapolatep et al., 2017 ; 2020a ,2020 b , 2020 c , 2020 d , 2022a , 2022b) both considered minor species at global level. A long series of drugs have been tested by independent scientists introducing new important data in animals that have been ignored so far.…”