Preparation of 20 (S)-protopanaxadiol PLGA Nanoparticles

[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was uniform.The encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.

Development of Prolonged Release Microspheres of Metformin Hydrochloride Using Ion Exchange Resins

Aim To prepare the prolonged-released microspheres of mefformin hydrochloride. Methods Ion-exchange resin-drug mefformin hydrochloride complexes were prepared as core materials, and followed by coating using ethylcellulose （EC） by the emulsion solvent diffusion technique. The release rate of mefformin from the microcapsules was highly dependent on the encapsulating formulation, thus being used as an index for formulation screening. Orthogonal experiments were performed to optimize the coating formulation. Results The final chosen formulation for coating of mefformin microcapsules were as follows： （ 1 ） the ratio of EC （20cps） to EC （45cps） was 50：50; （2） the ratio of plasticizer to coating materials was 20% ;and （3） the ratio of resin-mefformin complexes to coating materials was 5 ： 1. Conclusion The prolonged release microspheres of mefformin hydrochloride were successfully prepared.

Process conditions for preparing well-defined nano- and microparticles as delivery systems of alkyl gallates

Dextran-covered poly(D,L-lactide) (PLA) nano-and microparticles were prepared using an emulsion/solvent evaporation (or diffusion) process for the encapsulation of alkyl gallates (AGs).In the first step,a solution of PLA and AG in ethyl acetate was emulsified to give an aqueous phase containing a hydrophobically modified dextran,which acted as a stabilizer.The second step involved solvent evaporation or diffusion.The emulsification conditions were varied,which allowed for the preparation of nanoand microparticle suspensions covering a wide range of surface-average particle diameters from 0.1 μm (sonication) to 500 μm (stirring with a magnetic bar),with narrow and reproducible size distributions.Continuous microfluidic emulsification in a flow-focusing system led to well-defined microparticles,in the 10-50 μm range.Particles loaded with octyl gallate (OG) and nonyl gallate (NG) were obtained using the three processes,and we showed that the encapsulation efficiency of OG and NG varied significantly depending on the emulsification process.The effect of particle size on the mechanism of in vitro release of encapsulated AGs was investigated.The kinetics of release were controlled either by Fickian diffusion within the solid core or swelling and hydrolytic degradation of the PLA matrix,depending on the pH of the external medium.