An Experimental Study On Quercetin-loaded Submicro Lipid Particles Preparation Process

Quercetin has many pharmacological effects,such as vascular expansion,antitussive and anticancer activities,as well as broad biological activity.The current problem is that quercetin being extremely difficult to dissolve in water,and it is unstable under light and heat.The drug carrier matrix used in solid lipid particle is a kind of physiologically tolerant solid lipid.The drug diffusion rate is slow while the metabolite is safe and nontoxic.Inclusion of quercetin in a solid lipid drug delivery system is hopeful to promote oral absorption effect of quercetin and its application in vitro.Based on the background above,the main content of this research is as follows:(1)Quercetin-loaded cholesterol solid lipid particles were prepared successfully by solvent evaporation method.The experimental condition for smaller particle size was:the mass fraction of cholesterol was 0.4%,the mass fraction of F-127 was 2%,the emulsifying time was 5 min,and the curing speed was 90 r/min.There was a positive correlation between the embedding rate and the concentration of cholesterol in a certain range.The embedding rate of solid lipid particles increased first and then decreased with the increase of curing speed.The embedding rate decreased with the increase of mass fraction of F-127,the rotor speed and the volume ratio of water to oil.The influence of different process parameters on the particle size and the embedding rate was not synchronous.The average particle size of quercetin solid lipid particle was 265～683 nm under different process parameters.The zeta potential of oil in water emulsion was—39.5±0.13 mV,which meaned that the static stability of the emulsion was preferably in the first stage of the preparation process.The embedding rate of quercetin in solid lipid particles reached 83.41±0.79%.The solid lipid particles were in shape of flake,the size distribution was narrow,and there was a agglomeration phenomenon.(2)In this part,taking glycerol monostearate and cholesterol as wall material and F-127 as surfactant respectively,quercetin-loaded submicro lipid particles were prepared by emulsion solvent evaporation method.The orthogonal design was used to optimize the prescription parameters:mass fraction of cholesterol,mass fraction of glycerol monostearate,mass fraction of surfactant.The particle size and size distribution of quercetin-loaded submicro lipid particle,as well as embedding rate were determined.The appearance of quercetin-loaded submicro lipid particles,physical embedding state and its storage stability were investigated.According to the experimental results,quercetin-loaded submicro lipid particles showed homogeneous size distribution,appearing an approximate spherical shape with smooth surface,and the embedding rate reached 88.10%.The quercetin-loaded submicro lipid particles demonstrated a good physical embedding state and storage stability.In conclusion,quercetin-loaded submicro lipid particles,with simple preparation method and good physico-chemical properties,can have a great application prospect in medicine,cosmetics and other fields.The scavenging activity of DPPH free radical showed that the antioxidant activity of quercetin was retained.(3)In this part,the release regularity of quercetin-loaded solid lipid particles in the dissolution medium of pH=7.4 was studied.The cumulative release R(%)of quercetin-loaded solid lipid particles in the dissolution medium was fitted with the kinetic equation of the drug release model.The release rate of quercetin from solid lipid particles was slow,and the cumulative release rate was 66.24%after 48 h.The characteristic of release curve accords with the rule of double exponential release model.R2 was 0.9954 and the fitting equation was R=43.98(1-e0.04824t)+28.02(1-e1.316t)-0.3647.