Preparation of bacteriostatic microspheres loading potassium diformate using emulsification/external gelation

Abstract Potassium diformate (KDF) is a good substitute for antibiotics in animal feed. Based on the response surface methodology for optimizing the preparation conditions of microspheres. The optimal formulation was as follows: the concentration of ALG was 2 %, the concentration of CaCl2 was 2 %, and 0.4 mL of surfactant. The objective of the present study was to microencapsulate the KDF antibacterial microspheres by emulsification/external gelation. The structure, morphology and thermal properties of the obtained microspheres were characterized by XRD, SEM, FT-IR and TGA. Additionally, the encapsulation efficiency (EE%), loading capacity (LC%), antibacterial and slow-release properties of the prepared microparticles were evaluated. The results show that the optimized microspheres had spherical in morphology, in size, from 2 μm to 10 μm. Finally, the results of the in vitro antibacterial test showed that, when the concentration of antibacterial microspheres was 96 mg/mL, the antibacterial rates against Escherichia coli (E. coli) and Staphylococcus aureus were 89 % and 87 %, respectively, which effectively inhibited the excessive growth of the bacteria. The release kinetics model of the KDF microspheres in vitro revealed that the first-order release mechanism and Hixon-Crowell release mechanism were the primary release mechanisms, and the action time in the intestine could be delayed to 5 h.