Investigation of the effect of temperature regimes on the rheological properties of developed photoprotective cream

Actuality.The reasons for the rise in skin cancer include excessive ultraviolet radiation (UVR) and an aging population.UVR, which is the primary risk factor for skin cancer, can be modified.One way to protect the skin from excessive UV rays is to use sunscreens with high UVA and UVB protection (Perugini, 2019;Roik, 2019).Thus, the production of sunscreen cosmetic products is a key element in ensuring preventive measures against oncological-dermatological pathology.The authors have developed a composition for a photoprotective cosmetic product with ultraviolet filters that can provide a broad spectrum of UV protection based on pharmaco-technological research.Given the intended use of the photoprotective cream at higher temperatures than its storage, it was relevant to study the effect of temperature on the rheological properties of the developed cream, which is crucial for ensuring the quality assurance of the final product.The aim of the study was to determine the rheological (thixotropic) properties of the developed photoprotective cream and the effect of different temperature regimes on its stability. Material and methods. Rheological parameters of the cream were measured using a Brookfield Model DV-III rheometer (Brookfield, UK).Research results.The viscosity of cream decreases with increasing shear rate.Such behaviour is typical for many dispersed systems, including emulsions, which are often the basis of creams.It is related to the material's structural breakdown under shear.As temperature increases, viscosity decreases, which is typical for most fluids and viscoelastic materials.It has been established that the developed cream belongs to dispersed structured systems characterized by elastic-plastic-viscous properties.It has been proven that the developed cream exhibits non-Newtonian flow behavior and its flow begins after a certain mechanical stress is applied. Conclusion.The experimental studies confirmed the rationality of the developed photoprotective cream technology, which showed stability under different temperature regimes at 20, 25 (storage temperatures), and 32 (application temperature), ensuring product quality.The determination of thermal stability and colloidal stability of the developed cream indicates its stability.