Preparation And Characterization Of Controlled Release Polv (Lactic-co-Glvcolic Acid) Encapsulates Of Tea Polyphenols

Tea polyphenol is a natural chemical with good antioxidant and pharmacological effects,since it is easily oxidized in the air,it’s long-acting effects are restricted.To enhance its stability and meet the requirements of long-term sustained release,tea polyphenol loaded polymer microspheres was prepared.In this paper,EGCG/PLGA microspheres were prepared by double emulsion method in order to enhance the encapsulation efficiency and drug loading of EGCG in microspheres,and to achieve two weeks of sustained release of EGCG.Firstly,the characterization of EGCG solution was established for the drug control release system,and then,the effects of different process conditions on the encapsulation efficiency and drug loading rate of EGCG/PLGA microspheres were investigated.The optimal process conditions of high encapsulation efficiency and drug loading and microspheres with good surface morphology were optimized by four-factor three-level orthogonal design experiment.The release behavior of prepared microspheres was studied.The encapsulation efficiency of EGCG/PLGA microspheres was increased from about 30%to 80%by regulating the good synergies among the phases,especially the PLGA concentration in the oil phase.The drug loading increased from about 2%to more than 4%.In addition,EGCG/PLGA microspheres with no defect on the surface were obtained by controlling the concentration of CaCl2 in the external aqueous phase,and the average release of EGCG was achieved for two weeks.The results can provide guidance for the preparation of small molecule hydrophilic drugs in sustained release microspheres and are expected to be used in adjuvant therapy for skin diseases.The innovation of this study is as follows:By adjusting the synergy between the phases in the double emulsion method,the problem of low encapsulation efficiency and short release time of the water-soluble EGCG is solved.The encapsulation efficiency and drug loading of EGCG was improved and the microcapsule was able to achieve long-term sustained release.