ABSTRACT
Objective:To prepare the sustained release system of icariin(ICA)@ gelatin nanoparticles (GNPs)-polyactic-co-glycolic acid(PLGA)(ICA @ GNPs-PLGA), and to optimize the conditions. Methods:ICA@GNPs-PLGA sustained release system was prepared using two-step desolvation method and S/O/W emulsion solvent-evaporation technique.The effects of different conditions,such as the PLGA:GNPs mass ratio and the total quality of ICA added on the entrapment efficiency(EE)of ICA@GNPs-PLGA composite microspheres were detected to optimize the preparation process. The surface morphology of GNPs and ICA@GNPs-PLGA composite microspheres were observed by SEM.The EE and the release results of ICA@GNPs-PLGA in the sample were determined with HPLC.Results:The prepared composite microspheres and nanocomplex were were white powder.The SEM results showed that the composite microspheres and nanocomplexs were spherical,the surfaces were smoothy,and the particle size distribution range was 4-12 μm and 150-200 nm,respectively,relatively uniform.At a GNPs mass fraction of 6 mg,the critical concentration of PLGA in DCM ranged within 0.5%-1.0%.At a GNPs mass fraction of 12 mg,the critical concentration of PLGA in DCM ranged within 1.0%-2.0%.However,at a critical PLGA mass fraction lower than 0.25%,no fully formed composite microspheres were observed.Within the critical concentration,the average EE of ICA@GNPs-PLGA microspheres was higher than(62.00±1.25)%.In addition,the EE of ICA in the microspheres was negatively correlated with the quality of ICA added.The accumulative release rate was less than in 24 h and it was 65.21% in 40 d.Conclusion:The ICA@GNPs-PLGA microspheres with homogeneous particle size distribution,high EE,low initial burst and without agglomeration can be acquired under the optimized conditions.