Abstract

Using a nonrandomized crossover design, pharmacokinetic data were determined after a single dose of meloxicam was administered to American flamingos (Phoenicopterus ruber). Each individual bird received either one dose of intramuscular meloxicam (1.0 mg/kg IM; n = 6) or one dose of oral meloxicam (1.0 mg/kg PO; n = 6). Following a 4-week washout period, the routes of administration were exchanged between birds and each bird again received either one dose of intramuscular meloxicam (1.0 mg/kg IM; n = 6) or one dose of oral meloxicam (1.0 mg/kg PO; n = 6). Blood samples were obtained from ten minutes to 24 hours following administration of the drug. Pharmacokinetics were determined from plasma concentrations measured via high-performance liquid chromatography. Sequential plasma concentration vs. time data were analyzed using a non-compartmental approach. Differences between all the pharmacokinetic parameters tested were statistically significant. The oral administration resulted in least squares mean values of C_max and AUC_0-inf that were 15% and 39% of the respective intramuscular values. The half-life of the terminal phase after oral administration was approximately twice that after intramuscular administration. These results indicate that both the extent and rate of absorption are less after oral than after intramuscular administration. The rate of absorption after oral administration seems to be slow enough to result in an increased value of T_max (1.33 hr vs. 0.28 hr) and half-life (3.82 hr vs. 1.83 hr) in comparison with the intramuscular administration. This is characteristic of a phenomenon known as flip-flop, which is caused by a significant decrease in the rate of absorption.

* Presenting author