Gastric Acid-Protective and Intestinal Targeted Nanogels Enable Anti-Bacterial Activity of Cefquinome

To enhance the antibacterial activity of cefquinome (CEF) against <i>Escherichia coli</i>, a Carboxymethylcellulose sodium (CMCNa)/D-Mannosamine hydrochloride (DMH)-based nanogels delivery system capable of protecting CEF from gastric acid degradation while enabling intestinal sustained release and targeted antibacterial enhancement was developed. Systematic research was conducted on the best formulation, physicochemical characteristics, stability, gastrointestinal fluid-responsiveness, and antibacterial activity of the optimal formulation. The results showed that the optimized CEF nanogels demonstrated an enhanced loading capacity (13.0% ± 1.7%) and encapsulation efficiency (52.2% ± 1.0%). CEF nanogels appeared as uniform transparent spheres with a smooth surface under transmission electron microscopy and exhibited a three-dimensional porous network via scanning electron microscopy. More importantly, stability studies revealed that the CEF nanogels hold satisfactory stability. In addition, the formed CEF nanogels could effectively avoid the destruction of CEF by gastric acid in simulated gastric juice. In addition, they had the effect of slow and targeted release in the simulated intestinal tract. Compared to the free CEF, CEF nanogels have stronger antibacterial activity against <i>Escherichia coli</i>. In short, the prepared CEF nanogels had stronger antibacterial activity than CEF through sustained and targeted release.