Pharmacokinetic Comparison of Tylvalosin Tartrate Nanocrystal Suspension and Soluble Powder in Broiler Chickens After Oral and Intravenous Administration

This study was performed to investigate and compare the pharmacokinetic characteristics of tylvalosin tartrate in broiler chickens following oral administration of a nanocrystal suspension (PO-NM) or a soluble powder formulation (PO-SP), with intravenous administration (IV) of tylvalosin tartrate serving as the reference standard. A total of 30 healthy broiler chickens were randomly allocated into three groups (PO-NM, PO-SP, and IV; <i>n</i> = 10). Tylvalosin was administered at a dose of 25 mg/kg body weight (BW), and blood samples were collected at multiple time points from 0 to 24 h post-administration. Plasma concentrations of tylvalosin were quantified using a validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method, and pharmacokinetic parameters were calculated using non-compartmental analysis. The results showed no significant differences in the terminal elimination half-life (t_1/2λz) and mean residence time (MRT) between the two oral formulations. However, the time to maximum concentration (Tmax) of PO-NM (0.71 ± 0.09 h) was significantly shorter than that of PO-SP (1.42 ± 0.18 h) (<i>p</i> < 0.05), while the maximum plasma concentration (Cmax) of PO-NM (255.52 ± 111.88 ng/mL) was markedly higher than that of PO-SP (120.45 ± 45.82 ng/mL) (<i>p</i> < 0.05). Furthermore, the absolute bioavailability (F) of PO-NM (15.73 ± 4.29%) showed a modest increase compared with PO-SP (11.45 ± 4.66%); however, this difference did not reach statistical significance. Collectively, these findings demonstrate that the PO-NM formulation achieved faster absorption, higher peak plasma levels, and greater systemic exposure compared with PO-SP, without significantly altering the elimination process. Overall, nanoparticle formulation appears to enhance the oral pharmacokinetic performance of tylvalosin in broiler chickens, potentially reducing residue risks and offering substantial application value in poultry medicine.