Objective  To develop a new formulation of enrofloxacin nanoemulsion for spray administration, and evaluate its disease control effect using chicken model of systemic infection.

Method  The phase transition method was used, and single factor and orthogonal tests were performed to screen formulations and optimize the prescription. High-performance liquid chromatography (HPLC) was used to determine enrofloxacin content in nanoemulsion. Nanoparticle and zeta potential analyzer was used to measure the particle size and zeta potential of nanoemulsion. Pharmacodynamic experiments were performed using chicken models infected by Salmonella pullorum and Escherichia coli, and the control effects of spray adminstration of compound enrofloxacin nanoemulsion on bacterial diseases were evaluated.

Result  The nanoemulsion prepared in this experiment was an oil-in-water type, light yellow, clear and transparent, and had uniform droplet distribution. The average particle size was (10.79 ± 1.5) nm, the polydispersity index (PDI) was 0.446 and the zeta potential was −21.63 mV. The pharmacodynamic evaluation showed that the survival rates of preventive administration groups with high, medium and low doses were 90.0%, 83.3% and 73.3% respectively, which were significantly higher than that of the infection control group (26.7%) ( P<0.01).

Conclusion  The compound enrofloxacin nanoemulsion prepared in this study has stable properties. The ultrasonic spray administration has good control effects on chicken diseases due to systemic infection of Salmonella pullorum and Escherichia coli.