Pharmacokinetics and bioavailability of solid dispersion formulation of tilmicosin in pigs.

Abstract

Tilmicosin (TMS) is a semisynthetic macrolide antibiotic restricted to veterinary use but is only partially soluble in aqueous solutions, which limits its administration in treatments. We developed a strategy to enhance the supersaturated solubility of TMS using amorphous solid dispersion (SD). The dissolution profile shown that the dissolution rate of TMS-SD was obviously faster than TMS. The pharmacokinetics of tilmicosin (TMS) and tilmicosin solid dispersion (TMS-SD) in pigs after oral administration at a single dose of 50mg/kg b.w were investigated. The tmax of TMS-SD (2.50hr) was 1.80 times faster than TMS (4.50hr) (p<.05). There were no significant differences in the other PK parameters (Cmax , t1/2β , V/F, CL/F, MRT, and AUC0-inf ) (p>.05). The mean relative bioavailability of TMS-SD compared with TMS was 140.39%, according to the AUC0-inf values. These results demonstrated that the solid dispersion technique enhanced the bioavailability of TMS and the new formulation administered to animals via drinking water may be used as a therapeutic alternative for clinical treatments.