Pharmacokinetics of meloxicam in laying hens after single intravenous, oral, and intramuscular administration

• Published in: Journal of veterinary pharmacology and therapeutics Vol. 45; no. 5; pp. 488 - 494
• Main Authors: Shao, Hao‐Tian, Yang, Fang, Chen, Jun‐Cheng, Zhang, Mei, Song, Zhe‐Wen, Yang, Fan
• Format: Journal Article
• Language: English
• Published: 01.09.2022
• Subjects: extravascular bioavailability; HPLC; Jing Hong laying hens; meloxicam; pharmacokinetics
• ISSN: 0140-7783; 1365-2885
• DOI: 10.1111/jvp.13081

The objective of this study was to determine the pharmacokinetics of meloxicam after a single intravenous (IV), intramuscular (IM), and oral (PO) dose at 1 mg/kg body weight in Jing Hong laying hens. Blood samples were collected at predetermined time points. Plasma meloxicam concentrations were determined using a validated high‐performance liquid chromatography (HPLC) assay method and then subjected to a non‐compartmental analysis. After IV administration, meloxicam had a mean (±SD) volume of distribution at steady‐state (Vdss) of 206.50 ± 25.23 ml/kg, a terminal half‐life (t1/2λ) of 5.45 ± 0.53 h, and a total body clearance (Cl) of 26.48 ± 4.13 ml/h/kg. After PO and IM administration, meloxicam was absorbed relatively rapidly: the peak concentrations (Cmaxs) of 3.04 ± 0.56 and 8.94 ± 2.31 μg/ml were observed at 3.08 and 0.80 h, respectively. After PO and IM administration, the absolute bioavailability (F) was determined as 70.13% and 125.50%, respectively. Assuming that hens shared the same analgesic threshold of meloxicam (0.5 μg/ml) with humans, the plasma concentrations after three different routes (PO, IM, and IV) of administration were above this value for 16.7, 19.2, and 14.9 h, respectively.