Disposition of a long‐acting oxytetracycline formulation in Thai swamp buffaloes (Bubalus bubalis)

Abstract

The present study aimed to characterize the pharmacokinetic profile of oxytetracycline long-acting formulation (OTC-LA) in Thai swamp buffaloes, Bubalus bubalis, following single intramuscular administration at two dosages of 20 and 30 mg/kg body weight (b.w.). Blood samples were collected at assigned times up to 504 h. The plasma concentrations of OTC were measured by high-performance liquid chromatography (HPLC). The concentrations of OTC in the plasma were determined up to 264 h and 432 h after i.m. administration at doses of 20 and 30 mg/kg b.w., respectively. The C values of OTC were 12.11 ± 1.87 μg/mL and 12.27 ± 1.92 μg/mL at doses of 20 and 30 mg/kg, respectively. The AUC values increased in a dose-dependent fashion. The half-life values were 52.00 ± 14.26 h and 66.80 ± 10.91 h at doses of 20 and 30 mg/kg b.w, respectively. Based on the pharmacokinetic data and PK-PD index (T > MIC), i.m. administration of OTC at a dose of 30 mg/kg b.w once per week might be appropriate for the treatment of susceptible bacterial infection in Thai swamp buffaloes.

Pharmacokinetics, pharmacodynamics and dosing regimen of long-acting oxytetracycline in nile tilapia (Oreochromis niloticus)

“…This suggested that the absorption of the drug was rapid. These results are, however, inconsistent with previous reports in terrestrial animals including pigs (El Korchi et al, 2001), calves (Kumar and Malik, 1998) and buffaloes (Poapolathep et al, 2017) which slow absorption occurred after OTC-LA treatment. This might be due to different routes of administration.…”

“…Use of Symmetry ® C18 column (150 x 4.6 mm i.d., 5 µm) for chromatographic separation at ambient temperature and binary gradient of mobile phase consisting of 0.01M oxalic acid and acetonitrile: methanol (80:20 v/v) provided the optimal peak shape and good resolution for both OTC and the internal standard. However, the total run time of this method was quite longer than the previous method using similar column and mobile phase (Zhang and Li, 2007;Poapolathep et al, 2017). This might be from the different calibration method either the use of external standard calibration or the use of other compounds such as the internal standard which can be separated faster.…”

“…Long-acting formulations of OTC (OTC-LA) have widely been used in veterinary medicine to provide prolonged drug release into treated animal plasma, which provide extended long-lasting effects for days (AliAbadi and Lees, 2000). This advantage is (Kumar and Malik, 1998), goats (Aktas and Yarsan, 2017), pigs (El Korchi et al, 2001) and buffaloes (Poapolathep et al, 2017). Moreover, the PK studies of OTC-LA were expanded to some wildlife, tammar wallabies (McLelland et al, 2011) and reptiles such as American alligators (Helmick et al, 2004) and freshwater crocodiles (Poapolathep et al, 2020).…”

“…The HPLC procedure was modified from Poapolathep et al (2017). The mobile phase used in the binary gradient of elution was composed of 0.01M oxalic acid in deionized water (A) and acetonitrile: methanol (80:20 v/v) (B).…”

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

“…The OTC extraction method was performed as previously described [13,14] and revalidated in spiked plasma of the crocodiles. Briefly, 500 µL of freshwater crocodile plasma was deproteinated by adding 50 µL of 15% trichloroacetic acid in acetonitrile (ACN) in a 1-mL conic Eppendorf tube and then vortexed for 1 min.…”