Plasma pharmacokinetics and faecal excretion of ivermectin (Eqvalan paste) and doramectin (Dectomax, 1%) following oral administration in donkeys.

Ivermectin (IVM- Eqvalan paste, 1.87%) and doramectin (DRM-Dectomax 1%) were each administered orally to donkeys at 200 microgkg(-1) bodyweight. Blood and faecal samples were collected at predetermined times over 30 days and plasma pharmacokinetics and faecal excretion determined. Maximum plasma concentrations (C(max)) of IVM (23.6 ngml(-1)) and DRM (33.9 ngml(-1)) were obtained at (t(max)) 19.2 and 24h, respectively. The area under the concentration curve (AUC) of DRM (228.9 ngdayml(-1)) was significantly larger than that of IVM (119.3 ngdayml(-1)) and mean residence time (MRT) was 6.5 days for IVM and 9.1days for DRM. The highest (dry weight) faecal concentrations (9.33 microgg(-1) - IVM, 12.12 microgg(-1) - DRM) were detected at 55.9 and 48.0 h, respectively and each compound was detected (0.05 microgg(-1)) in faeces between 11h and 9 days following oral administration in donkeys.