Abstract: Objective: To use polylactic-co-glycolic acid(PLGA) as vector material to prepare the compound total flavonoids of Rhizoma Drynariae(TFRD) and total flavonoids of Chrysanthemum(TFC) sustained release microcapsuleTF-PLGA microcapsules,and to investigate the the best preparation technique of TF-PLGA microcapsules and their sustained release characteristics in vitro. Methods: The TF-PLGA microcapsules were prepared with TFRD,TFC, and PLGA by emulsifying-solvent evaporation technique under certain conditions.With the encapsulation efficiency(EE) as the evaluation indicator,the optimal formulation was verified by single factor experiment and orthogonal design;the general morphology,the particle size and distribution of the microcapsules were observed by light microscope(LM) and scanning electron microscope(SEM);the cumulative drug release rate of TF-PLGA microcapsules was detected by constant temperature commotion method in vitro and the release curves of the TF-PLGA were drawn. Results: The optimal prescription was as follows:the concentration of PLGA was 140 g·L^-1,oil phase volume was 1.4 mL,emulsifying speed was 900 r·min^-1,emulsifying time was 5 min,the average EE was(83.89±2.30)%,and the average drug loading rate(DL) was(5.90±0.07)%.The LM and SEM resluts showed that the TF-PLGA microcapsules presented as round ball,the average particle size was(44.34±14.68)μm, and the distribution was relatively narrow.The drug release in vitro results showed that the initial drug release rate(24 h)was about 40%,and the cumulative drug release rate was over 90% after 50 d. Conclusion: The TF-PLGA sustained release microcapslue has better drug-loaded and sustained-release effects with simple preparation technique and better repeatability.

Key words: total flavonoids of Rhizoma Drynariae, total flavonoids of Chrysanthemum, slow-release, polylactic-co-glycolic acid, microcapsules