Preparation Of Emulsion Microspheres Loaded With Potassium Dicarboxylate And Their Antibacterial Properties

Long-term use of antibiotics as feed additives will lead to intestinal flora disorder,causing bacterial and fungal double infection.Non-antibiotic potassium dicarboxylate（KDF）can effectively improve feed utilization and avoid antibiotic resistance.Due to the rapid release of KDF in the stomach,the utilization rate in the intestine was low,which was not conducive to the full play of the antibacterial effect.In order to achieve targeted release at the colon site,this study prepared emulsion antibacterial microspheres loaded with KDF by constructing two emulsion systems,and added Zeolite P to the internal aqueous phase to improve drug loading rate and encapsulation rate.The preparation process of the microspheres were optimized to improve the stability of the microspheres in the release system.The composition,structure,morphology and thermal properties of the optimized microspheres were analyzed through testing and characterization.The drug release,bacteriostatic and in vitro degradation experiments showed that the microspheres had good slow-release and bacteriostatic properties,and could degrade green and environmentally friendly.The main conclusions were as follows:（1）Pectin with colon properties as the wall material,with Ca²⁺to form an"egg box structure"to form the internal water phase,good adsorption Zeolite P loaded KDF distribution,the preparation of single-phase emulsion microspheres.It was proved by testing that the sample was spherical,which could effectively enclose KDF,and the structure stability was improved by added Zeolite P,which was a drug binding agent.The simulated release experiment showed that the microspheres were p H sensitive,and the release amount in alkaline environment was higher than that in acidic environment.After adding Zeolite P,the drug encapsulation rate and load rate were improved,because Zeolite P can adsorb grafted KDF,and the release rate was higher in the same simulated release environment,which confirmed that Zeolite P,as a drug binding effector,can effectively increase the drug load so as to improve the utilization rate in the intestine.（2）Xanthan gum（XG）formed a multiphase emulsion system due to the combination of negative electric properties and positive chitosan（CS）as an external aqueous phase through polyelectrolyte.After characterization test,it was found that the structural stability of the whole emulsion system was enhanced compared with single-phase emulsion microspheres.After KDF was grafted on Zeolite P,the multiphase emulsion microspheres were prepared for release simulation experiment.It was found that the microspheres prepared by the multiphase system improved the encapsulation rate and drug loading rate of KDF,and the release amount in the intestine was higher than that of single-phase emulsion microspheres and effectively delayed the release of drugs,with p H sensitivity.The external water phase with polyelectrolyte composite characteristics enables the multiphase emulsion microspheres to have a stable structure-activity relationship and increase the load of KDF,which can be used as a new drug loading system for intestinal targeted drug delivery.（3）The above two systems all follow the Ritger-Peppas model of release kinetics,and the release mechanism belonged to classical Fick diffusion.It had antibacterial effect on Escherichia coli（E.coli）,Staphylococcus aureus（S.ureus）and Bacillus subtilis（B.subtilis）.The maximum bacteriostatic rates of single-phase emulsion microspheres were 84.91%,81.36%and 83.46%,respectively,which were effective in balancing the growth of bacteria in intestinal tract.In order to give full play to the antibacterial effect of KDF,XG and CS were added into the external aqueous phase to form a stable fabric relationship of the loaded system,and the maximum antibacterial efficiency of E.coli,S.ureus and B.subtilis were increased to 97.25%,94.05%and95.9%.