Residue depletion profile and withdrawal interval estimation of ivermectin in eggs following topical administration of injectable ivermectin to domestic chickens (Gallus domesticus): a pilot study

This study improves the understanding of the residue depletion kinetics of ivermectin in eggs after topical administration to older hens with inconsistent egg production. Ivermectin is systemically absorbed following topical administration of the injectable formulation in domestic egg laying chickens, resulting in prolonged egg residues. Ivermectin is preferentially distributed to the egg yolk over the egg white following topical administration of the injectable formulation in egg laying chickens. Since plasma kinetics were not evaluated, the impact of systemic exposure on egg residue kinetics following topical administration remains unknown. The results provide insight into how the estimated ivermectin egg WDIs using regulatory methods differ based on the maximum residue limit/tolerance applied and portion of the terminal elimination phase sampled.