Pharmacokinetics of amoxicillin trihydrate in male Asian elephants (Elephas maximus ) following intramuscular administration

The bioavailability and pharmacokinetics of an amoxicillin-clavulanic acid granular combination after intravenous and oral administration in swine

The pharmacokinetic behaviours of amoxicillin (AMX) and clavulanic acid (CA) in swine were studied after either an intravenous or oral administration of AMX (10 mg/kg) and CA (2.5 mg/kg). The concentrations of these two medicines in swine plasma were determined using high-performance liquid chromatographic-tandem mass spectrometry, and the data were analysed using a noncompartmental model with the WinNonlin software. After intravenous administration, both substances were absorbed rapidly and reached their effective therapeutic concentration quickly. CA was eliminated more slowly compared with AMX. Moreover, the distribution volume of AMX was larger than that of CA, suggesting that AMX could penetrate tissues better. After oral administration of the granular formulation, no significant difference was observed in the mean elimination half-life value between AMX and CA. The mean maximal plasma concentrations of AMX and CA, reached after 1.14 and 1.32 hr, were 2.58 and 1.91 μg/m, respectively. The mean oral bioavailability of AMX and CA was 23.6% and 26.4%, respectively. After oral administration, the T>MIC₅₀ for three common respiratory pathogens was over 6.12 hr. Therefore, oral administration could be more effective in the clinical therapy of pigs, especially when administered twice daily.

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

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 (t_{1/2λ z} ) 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.

Pharmacokinetics of amoxicillin trihydrate in Thai swamp buffaloes (Bubalus bubalis): a pilot study

This study aimed to investigate the pharmacokinetic characteristics of amoxicillin (AMX) in Thai swamp buffaloes, Bubalus bubalis, following single intramuscular administration at two dosages of 10 and 20 mg/kg body weight (b.w.). Blood samples were collected at assigned times up to 48 h. The plasma concentrations of AMX were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of AMX in the plasma were determined up to 24 h after i.m. administration at both dosages. The C_max values of AMX were 3.39 ± 0.18 μg/mL and 6.16 ± 0.18 μg/mL at doses of 10 and 20 mg/kg, respectively. The AUC_last values increased in a dose-dependent fashion. The half-life values were 5.56 ± 0.40 h and 4.37 ± 0.23 h at doses of 10 and 20 mg/kg b.w, respectively. Based on the pharmacokinetic data and PK-PD index (T > MIC), i.m. administration of AMX at a dose of 20 mg/kg b.w might be appropriate for the treatment of susceptible Mannheimia haemolytica infection in Thai swamp buffaloes.