| Resveratrol(Res),a characteristic active substance of forest source,is a non-flavonoid natural polyphenol compound widely present in the roots,stems,leaves,and other organs of many plants.Res has many pharmacological activities such as anti-oxidation and anti-tumor.However,due to the large crystals and unstable chemical properties as well as other defects,it is difficult to be effectively absorbed and utilized,leading to its limited development in the fields of food,medicine,and health products.Therefore,targeted improvement of the above shortcomings of Res has become one of the key issues in the research and development of resveratrol at this stage.In this thesis,shellac resin ammonium salt(SRAS)modified by ammonia water was used as the drug-carrying substrate,Res was highly dispersed in the drug-carrying substrate.Then,resveratrol solid dispersion was prepared by electrospinning and spray drying.The material characterization and performance of the solid dispersion were studied,and the in vitro release characteristics and the analysis of the release mechanism was explored.Furthermore,the pH-sensitive material L-histidine(L-His)was incorporated to prepare a pH-sensitive SRAS-His/Res solid dispersion.Finally,the anti-tumor activity of human colon cancer HCT116 cells was evaluated.The main results achieved were as follows:(1)SRAS/Res-ES and SRAS/Res-SD solid dispersions were prepared by electrospinning and spray drying.The dosages of SRAS,Res,and absolute ethanol in the optimized formula were 2.0 g,0.222 g,and 10 mL,respectively.Under this condition,the embedding rate and loading rate of Res in SRAS/Res-ES prepared by electrospinning were 79.06%and 7.91%,and the embedding rate and loading rate of Res in SRAS/Res-SD prepared by spray drying method were 85.48%and 8.55%,respectively.The material characterization analysis by SEM,FT-IR,DSC,and XRD showed that:Res was successfully encapsulated in SRAS,the particle size of SRAS/Res-ES and SRAS/Res-SD about 843.75±162.99nm and 28.97±4.68 μm,respectively.Res existed in solid dispersion in amorphous form,and its thermodynamic properties were more stable.Anti-oxidation and in vitro release studies showed that:the anti-oxidation ability of solid dispersion was higher than that of Res.SRAS/Res-ES prepared by electrospinning had a higher cumulative release rate than Res and appeared a certain enteric solubility.(2)Under the pre-optimized formula conditions,the pH-sensitive material L-histidine(L-His)was added,and the Res-loaded solid dispersion(SRAS-His/Res-ES and SRAS-His/Res-SD)was prepared by electrospinning and spray drying.The material characterization showed that after adding L-His,the micromorphology and particle size distribution of the prepared SRAS-His/Res-ES and SRAS-His/Res-SD were slightly changed.The shapes were all spherical structures with a smoother surface,and the particle sizes about 898.08±173.62 nm and 30.63±7.5 μm,respectively.At the same time,the chemical composition,amorphous structure,and thermal stability of the solid dispersion did not significantly affect it.Anti-oxidation and in vitro release studies showed that:after adding L-His,the anti-oxidation capacity of the prepared solid dispersion was higher than that before and Res.Res can be released slowly for 2 hours in a simulated gastric fluid and can be quickly released 2 hours before simulating intestinal fluid,which appeared as an obvious burst release phenomenon.After reaching a certain concentration,the remaining Res can continue to be released slowly,appeared a certain pH response characteristic.When released for 12 h under simulated human physiological environmental conditions,the cumulative release rates of SRAS-His/Res-ES and SRAS-His/Res-SD reached 95.62%and 55.02%,and SRAS-His/Res-ES appeared more pH response characteristics.(3)The cumulative release effects of Res,SRAS/Res,and SRAS-His/Res solid dispersions released in the simulated intestinal fluid within 10 h were fitted to the zero-order,first-order,Higuchi equation,and Ketger-Peppas(K-P)kinetic equation model respectively.The release of Res conformed to the Higuchi equation,the release mechanism belonged to Fick diffusion release.The SRAS/Res-ES and SRAS-His/Res-ES both fit the first-order kinetic model best,which belongs to the joint assisted release of drug diffusion and matrix erosion.The release of Res in SRAS/Res-SD and SRAS-His/Res-SD conforms to the K-P equation kinetic model,and the release is dominated by skeleton dissolution.(4)The MTT method was used to study the inhibitory effects of different concentrations of Res,SRAS/Res-ES,and SRAS-His/Res-ES sustained-release solutions on colon cancer HCT116 cells.The positive control of the experiment was Fluorouracil(5-FU).The results showed that when the concentration of Res,SRAS/Res-ES,and SRAS-His/Res-ES was less than or equal to 120 μM,the inhibition rate on HCT116 cells was less than 50%,which was drug-insensitive or moderately sensitive,and the inhibitory effect on HCT116 was not significant.When the 5-FU concentration was 120～160 μM,and when the concentration of Res and SRAS-His/Res-ES was 160 μM,the inhibition rate can reach>50%,indicated that the drug was sensitive and appeared a significant inhibitory effect on HCT116.Among them,the inhibition rate of Res and SRAS-His/Res-ES sustained-release solution at a concentration of 160 μM was similar.SRAS-His/Res-ES can release Res relatively completely,in addition,shows a significant inhibitory effect on colon cancer HCT116 cells. |
