Objective: A ceftiofur hydrochloride long-acting oily suspension with no irritation was
prepared by testing and optimizing the types and amounts of organic solvents, suspending agents,
Methods: Its properties, stability, injection site irritation, in vitro release, and pharmacokinetics in
pigs were evaluated. The optimum formulation was used ethyl oleate, aluminum monosterate, and
span-80 as organic solvents, suspending agents, and surfactant, respectively. The drug microparticles
were uniform long strip with size of 1.53 ± 0.11 μm and no agglomerations, and were evenly
dispersed. The re-dispersed time, sedimentation rate and pH value of the suspension were 4 s under
a magnetic shaker rotating at 20 r/min, 1 and 5.0, respectively. It could go through 7-gage needle
smoothly with withdrawal volume of 9.9 mL/min.
Results: The suspension showed good stability when stored away from light, no irritation at the injection
site and sustained release in PBS buffer. After intramuscular administration, the drug concentration
above 0.15 μg/mL was last for 120 h. Its elimination half-life (T1/2ke), mean residence
time (MRT), and bioavailability were increased by 1.73, 1.62, and 2.16 times compared to
Conclusion: The results suggested that the suspension had excellent sustained-release and will
make ceftiofur hydrochloride more effective and convenient to use.