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

## TL;DR

This study compares how well a drug called tylvalosin is absorbed in chickens when given in two different forms, finding that a nanocrystal suspension works faster and better than a soluble powder.

## Contribution

The study introduces a nanocrystal suspension formulation of tylvalosin that improves absorption and peak concentration in broiler chickens compared to traditional soluble powder.

## Key findings

- The nanocrystal suspension (PO-NM) had a significantly shorter time to reach maximum concentration (Tmax) compared to the soluble powder (PO-SP).
- PO-NM achieved a higher maximum plasma concentration (Cmax) than PO-SP, indicating better absorption.
- The absolute bioavailability of PO-NM showed a modest increase compared to PO-SP, though not statistically significant.

## Abstract

This study evaluated how tylvalosin behaves in chickens when given as two different oral formulations—a nanocrystalline suspension and a soluble powder—compared with intravenous administration. Thirty healthy broilers received a single dose of 25 mg/kg, and blood samples were analyzed by UPLC-MS/MS. The nanocrystalline suspension was absorbed faster and reached higher blood levels than the soluble powder. Although the overall bioavailability of tylvalosin remained low, the nanocrystalline formulation provided modest improvement, suggesting potential benefits in reducing dosage and drug residues in poultry.

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; n = 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 (t1/2λz) 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) (p < 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) (p < 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.