Pharmacokinetics of a new ivermectin/praziquantel suspension after intramuscular administration in sheep

- A new ivermectin/praziquantel suspension was developed successfully.
- The pharmcokinetics of praziquantel in the combination product were improved.
- Our product may be an alternative choice for sheep to control parasites infection.

A new oil suspension containing 0.10% ivermectin (IVM) and 15% praziquantel (PZQ) (Tivm+pzq) for intramuscular injection was developed for sheep, and its pharmacokinetics was investigated in sheep. The quality of the new product met the technical standards set by the Ministry of Agriculture of the People's Republic of China. In pharmacokinetics, the commercially available single-component products approved by the Chinese Ministry of Agriculture and widely used in the livestock industry in China were selected as reference products (Rivm and Rpzq). The results showed that all of the IVM pharmacokinetic parameters of Tivm+pzq were similar to those of the reference. However, after adminstraion of Tivm+pzq, mean residence time (MRT) and plasma elimination half-life (t1/2z) were 20.36 h and 11.65 h, which were 2.61 and 3.22 times longer than those of Rpzq (7.81 h and 3.62 h). In summary, the MRT and t1/2z of PZQ in Tivm+pzq were prolonged and IVM pharmacokinetic parameters were similar to commerical product, therefore the new injection may be an alternative choice for sheep to control parasites sensitive to IVM and PZQ.