ABSTRACT
With increased ownership of backyard poultry, veterinarians must treat these birds appropriately and take into consideration drug withdrawal times for eggs meant for consumption. Few studies have examined the pharmacokinetics or egg residues for medications commonly used in avian medicine. This study determined the pharmacokinetics of meloxicam in domestic chickens (n = 8) after oral dosing at 1 mg/kg q12h for a total of 9 doses (5 days). Additionally, the presence of meloxicam residues in eggs was determined. The terminal half-life, maximum concentration, and time to maximum concentration were 3.02 ± 1.15 hours, 7.14 ± 1.54 µg/mL, and 1.6 ± 0.52 hours, respectively. No drug was detected in yolks and whites after 8 days and 3 days, respectively. On the basis of these results, a 2-week withdrawal time should be adequate to avoid drug residues in eggs meant for consumption.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacokinetics , Chickens/metabolism , Drug Residues/analysis , Eggs/analysis , Meloxicam/pharmacokinetics , Administration, Oral , Animals , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Anti-Inflammatory Agents, Non-Steroidal/analysis , Anti-Inflammatory Agents, Non-Steroidal/isolation & purification , Chickens/physiology , Chromatography, High Pressure Liquid/veterinary , Egg White/chemistry , Egg Yolk/chemistry , Female , Half-Life , Meloxicam/administration & dosage , Meloxicam/analysis , Meloxicam/isolation & purification , Time FactorsABSTRACT
OBJECTIVE To determine the pharmacokinetics of meloxicam in domestic hens and duration and quantity of drug residues in their eggs following PO administration of a single dose (1 mg of meloxicam/kg). ANIMALS 8 healthy adult White Leghorn hens. PROCEDURES Hens were administered 1 mg of meloxicam/kg PO once. A blood sample was collected immediately before and at intervals up to 48 hours after drug administration. The hens' eggs were collected for 3 weeks after drug administration. Samples of the hens' plasma, egg whites (albumen), and egg yolks were analyzed by high-performance liquid chromatography. RESULTS The half-life, maximum concentration, and time to maximum concentration of meloxicam in plasma samples were 2.8 hours, 7.21 µg/mL, and 2 hours, respectively. Following meloxicam administration, the drug was not detected after 4 days in egg whites and after 8 days in egg yolks. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that meloxicam administered at a dose of 1 mg/kg PO in chickens appears to maintain plasma concentrations equivalent to those reported to be therapeutic for humans for 12 hours. The egg residue data may be used to aid establishment of appropriate drug withdrawal time recommendations.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacokinetics , Chickens/metabolism , Drug Residues/metabolism , Eggs , Thiazines/pharmacokinetics , Thiazoles/pharmacokinetics , Administration, Oral , Animals , Chromatography, High Pressure Liquid/veterinary , Egg Yolk , Female , Half-Life , MeloxicamABSTRACT
A new method of analysis has been developed and validated for the determination of meloxicam in egg whites and yolks. Following a liquid extraction for the whites and a solid phase extraction for the yolks, samples were separated on an XBridge C18 column and quantified using ultraviolet detection at 360 nm. The mobile phase was a mixture of water with glacial acetic acid and acetonitrile, with a flow rate of 1 mL/min. The procedure produced a linear graph over the concentration range 5-1500 ng/mL with a lower limit of quantification of 5 ng/mL. Intra- and inter-assay variability was 10% or less for both the whites and yolks. The average recovery for whites was 96% and the average recovery in yolks was 97%.
