Determination of total C-14 residues of sarafloxacin in eggs of laying hens

[C-14]Sarafloxacin was orally administered to six laying hens for five cons ecutive days. Eggs were collected for 15 days after the initial drug treatm ent. Egg yolk and egg albumen were separated and assayed for total radioact ive residues (TRR) using a combustion oxidizer and scintillation counting t echniques. Radioactivity was detected in egg yolk and egg albumen on the se cond day of dosing and reached a maximum at 24 h after drug withdrawal. The reafter, the sarafloxacin TRR levels in egg albumen declined rapidly and we re undetectable 2 days after the last dose, whereas the levels in egg yolk declined at a much slower rate and were undetectable 7 days after drug with drawal. In both the egg albumen and yolk, HPLC analysis indicated that the parent sarafloxacin was the major component.