| Oxidation and ultraviolet radiation are major causes of skin aging. Antioxidation andsunscreen have become to be one of research hotspots in the field of cosmetics and toiletries.The applications of Vitamin E, which is a kind of fat-soluble antioxidant, have been limited bysome characteristics, such as hydrophobic property and easy oxidation. The widespread use ofordinary emulsifier in common sunscreen cream has lead to big stimulation on skin and noparticipate in helping maintain the stability of emulsion, due to the mainly exist areas ofsunscreen particles are in the external phase of emulsion. In this dissertation, aiming at theshortcomings of the existing technologies, the influence of micro-emulsion and Pickeringemulsion on skin is studied on in two aspects of antioxidant and sunscreen. Vitamin E is usedas oil phase during the preparation of micro-emulsion for the purpose of protection and capacityexpansion of vitamin E. Mesoporous silicon is used as particle stabilizers for the preparation ofPickering emulsion, which is stability in thermodynamics. The main research contents of thisdissertation are as follows:1. The research of blank vitamin E micro-emulsionThe optimum formula and optimal preparation technology of blank vitamin E micro-emulsion are obtained respectively through the pseudo-ternary phase diagram and the singlefactor experiment. Five groups of vitamin E micro-emulsion is prepared with taking points inpseudo-ternary phase diagram. Physical and chemical properties and stability of the samplesand loading capacity and stability of vitamin E are investigated using some analysistechnologies, such as PH meter, conductivity meter, surface tensiometer, Melvin lasergranulometer, TEM, UV-Vis, etc. Analysis of the formation of the microemulsionBythermodynamic. The experimental results show that the samples are O/W micro-emulsion,acting weak acidity, with granularity between10~30nm and good stability. Microemulsion canform spontaneously.The stability of vitamin E in micro-emulsion performs well.2. Preparation and quality evaluation of medicine carrying vitamin E micro-emulsionPseudo-ternary phase diagram of medicine carrying micro-emulsion is portrayed using theknown optimum formula. Five groups of salicylic acid micro-emulsion is prepared with takingpoints in the diagram. Physical and chemical properties and stability of the samples and therelease of salicylic acid and water molecules in the system are investigated using some analysistechnologies, such as PH meter, conductivity meter, surface tensiometer, Melvin lasergranulometer, TEM, UV-Vis, XRD, etc. The experimental results show that the samples areO/W micro-emulsion, acting acidity, with granularity between10~40nm and good stability. The release of salicylic acid has sustained release effect, and the system contains watermolecules in four different states.3. Evaluation of effect of vitamin E micro-emulsion on antioxidation and stratum corneumThe antioxidation of vitamin E micro-emulsion and medicine carrying micro-emulsion isanalyzed through DPPH and ABTS radical scavenging experiment. The experimental resultsshow that the micro-emulsion have antioxidant effect. Due to different formulations antioxidantvary. Moreover, the antioxidant effect are enhanced by mixing with salicylic acid. The influenceof micro-emulsion on stratum corneum is studied using FTIR and SEM characterizationmethods. The analysis results show that the micro-emulsion is able to make the skin keratinloosen. Medicine carrying micro-emulsion is able to play a role of salicylic acid in addition toreducing the stimulation to skin.4. The preparation technology of mesoporous silica stable Pickering emulsion and themeasurement of its sun protection factorThe prepared mesoporous silica are characterized through small Angle XRD, BET, TEM,UV-Vis.The results show that it has mesoporous structure, with specific surface area of988.9m2/g-1and hole size of3.43nm. The channel structure is relatively uniform and the uvabsorbance value is relatively high at280~320nm of the channel. Mesoporous silica particlesas Pickering stabilizer prepare stable emulsion，optimal formula are obtained through stabilityexperiments. The type, stability and microstructure of Pickering emulsion prepared with theoptimum formula are studied on through3d confocal microscope, conductivity meter, UV-Vis.The measurement of its sun protection factor are made as well. The results show that thePickering emulsion is O/W type. The particles have size of around50m, with homogeneousdistribution and good stability. The SPF value is acquired as above5by measuring the uvtransmission spectra and PA is over one+. |
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