An interest in nanostructured lipid formulations for skincare has increased in recent years because they have been looking for new methods of incorporation of cosmetic active ingredients to achieve the best possible delivery and the effect consequently. The development of optimal delivery systems is essential for a successful dermal application. Self-microemulsifying systems represent a promising approach for the incorporation of cosmetic active ingredients with poor water solubility. Microemulsions relieve their penetration into the skin. They are thermodynamically stable and offer a local effect. (Lamellar) liquid crystals have a great solubilizing ability. They improve the chemical stability of incorporated ingredients and do not irritate the skin because they are similar to intercellular lipids in structure. Simultaneously, we incorporated lipophilic antioxidants (vitamin E and ascorbyl palmitate), which slow down oxidative skin injuries and, thus, photoaging, into the self-microemulsifying system, microemulsion of waters in oil, lamellar liquid crystals, and microemulsion of oil in water which were constructed from the same components but in different ratios. The purpose of the bachelor’s thesis was to ascertain which of the selected delivery systems is more appropriate for the dermal delivery of the incorporated vitamins and, consequently, the expression of antioxidant activity in the skin. We were interested in the influence of viscosity and internal structure of the delivery system on the release of the incorporated vitamins, which we evaluated by the in vitro method of releasing vitamin E and ascorbyl palmitate through the cellulose membrane in Franz diffusion cells. We defined the differences in the internal structure of the studied systems by rheological tests with and without incorporated vitamins. We confirmed that the internal structure of the delivery systems which is dependent on the content of substances active on surface and water also influences the viscosity of the systems importantly, in addition to the consistency of individual excipients. Following the expectations and organoleptic examination, we measured the highest viscosity to lamellar liquid crystals where the latter was pretty independent of the presence of the incorporated vitamins. In the studied time interval, both vitamins were released to the greatest extent from the self-microemulsifying system which is the least viscid out of all systems and, already by definition, has a high affinity toward the water phase in touch with which it forms microemulsions spontaneously. Contrary to the expectations, the release of vitamins from lamellar liquid crystals was not slower as from other systems. Amphiphilic ascorbyl palmitate was indeed released from all systems to a higher extent in comparison to more lipophilic vitamin E. The results show that the internal structure of the delivery systems and characteristics of the incorporated vitamins influence the release of the latter more than rheological characteristics of the studied systems.
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