Comparison of an injectable toltrazuril-gleptoferron and an oral toltrazuril + injectable gleptoferron in piglets: Hematinic activities and pharmacokinetics.

Iron deficiency anemia (IDA) and cystoisosporosis are the most common clinical conditions of fast-growing piglets. Until now, IDA and cystoisosporosis have been managed by intramuscular injection of iron complexes (such as dextran or gleptoferron) and oral administration of toltrazuril. Recently, a new combination product containing toltrazuril and gleptoferron for intramuscular application (Forceris®) has been registered. The objective of this study was to compare the pharmacokinetic profiles of toltrazuril and its main metabolite, toltrazuril sulfone, following a single oral (Baycox®) or intramuscular (Forceris®, a toltrazuril-iron combination product) administration at 20 mg/kg to young suckling piglets. The orally treated piglets were also supplemented with iron (Gleptosil®), and the hematinic activities were compared. Piglets in both groups received comparable doses. The peak concentration (C_max) of toltrazuril after intramuscular administration was 11% lower than that after oral administration (p = .376). However, the exposure to toltrazuril (AUC) was significantly increased (40% higher) when toltrazuril was administered intramuscularly (p = .036). The C_max and AUC values of the active metabolite, toltrazuril sulfone were 39% and 34% higher, respectively, after intramuscular administration (p = .007 and 0.008, respectively). Piglets in both groups were properly protected against IDA. In conclusion, a higher relative bioavailability of toltrazuril is observed when toltrazuril is administered intramuscularly.