Percentage of faecal excretion of meloxicam in the Cape vultures (Gyps corprotheres).
Asian Gyps vulture species are gradually recovering from the devastating effect of diclofenac being present in contaminated carcasses. This drug was responsible for the death of over 10 million vultures in India, Nepal and Pakistan. To prevent the extinction of vultures, meloxicam was introduced after the ban of veterinary diclofenac. Meloxicam's safety in vultures was attributed to its short elimination half-life in contrast with diclofenac. The reason for the rapid elimination of meloxicam is yet to be explained. The aim of this study was to evaluate the role of biotransformation in the elimination of meloxicam. Six Cape griffon vultures (Gyps coprotheres) were treated with 2 mg/kg meloxicam intramuscularly for faecal and plasma quantification of meloxicam concentration over time. In the plasma meloxicam was characterised by a half-life, mean residence time, clearance and volume of distribution at steady state of 0.37 ± 0.10 h, 0.90 ± 0.12 h, 0.02 ± 0.00 l/h kg and 0.02 ± 0.00 l/kg respectively (presented as geometric mean). Over the 24 h monitoring period, the total non-metabolised meloxicam in the faeces was 1.35 ± 0.71% of the total concentration in the plasma. Based on the short meloxicam elimination half-life and low cumulative concentration of total faecal meloxicam over a period in excess of 10 half-lives, this study indicates that Cape griffon vultures are efficient metaboliser of meloxicam, which is suggestive of different set of cytochrome enzymes being involved in the metabolism to that for diclofenac in this species. Identification of orthologous human CYP2C9 and CYP3A4 enzyme families in vultures will be an important further step in explaining the differences in the metabolic pathway(s) of meloxicam and diclofenac for the species.
['Adawaren|Emmanuel Oluwasegun|EO|', 'Mukandiwa|Lillian|L|', 'Chipangura|John|J|', 'Wolter|Kerri|K|', 'Naidoo|Vinny|V|']
D000818:Animals D000894:Anti-Inflammatory Agents, Non-Steroidal D001711:Biotransformation D060435:Carnivory D004008:Diclofenac D004350:Drug Residues D056727:Endangered Species D004785:Environmental Pollutants D046093:Falconiformes D005243:Feces D006207:Half-Life D007273:Injections, Intramuscular D066237:Intestinal Elimination D000077239:Meloxicam D008657:Metabolic Clearance Rate D008954:Models, Biological D015203:Reproducibility of Results D013019:South Africa D066007:Toxicokinetics D019155:Veterinary Drugs
Meloxicam Gyps vulture Diclofenac Elimination half-life Metabolism