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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Application of Factorial Design and Rheology to the Development of Photoprotective Formulations

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Ferreira, V. T. P. [1] ; Infante, V. H. P. [1] ; Felippim, E. C. [1] ; Maia Campos, P. M. B. G. [1]
Total Authors: 4
[1] Univ Sao Paulo, Sch Pharmaceut Sci Ribeirao Preto, Ave Cafe S-N, BR-14040903 Ribeirao Preto, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: AAPS PHARMSCITECH; v. 21, n. 2 JAN 3 2020.
Web of Science Citations: 0

A sunscreen should form a stable and homogeneous film over the skin surface, which can improve its photoprotective activity and avoid adverse effects. For this purpose, the definition of the appropriate vehicle is of fundamental importance since emulsifying agents are known to directly influence the stability, sensorial properties and surface tension of sunscreens, modulating their film-forming performance. In this context, the objective of the present study was to systematically develop formulations with UVB/UVA protection and evaluate the effect of wax concentration on the rheological behaviour. A 2-level full factorial design was applied for the development of four formulations. Two categorical factors were evaluated, glyceryl stearate plus PEG-75 stearate (Wax 1) and methyl glucose sesquistearate (Wax 2). Rheological behaviour was determined in triplicate and rheograms were analysed using the Ostwald model. Rheological parameters were correlated by the Spearman rank correlation test and effects were evaluated by Pareto chart and surface response methodology (SRM). It was possible to identify the pseudoplastic and thixotropic behaviour of all formulations exhibiting a thinning effect on higher shear stress. Factorial analysis showed that both waxes significantly influenced consistency and thixotropic behaviour. The effect of Wax 2 concentration in thixotropy was positive and of higher magnitude and a synergistic effect was also observed. Spearman correlation coefficient of consistency index and apparent viscosity was significantly strong and positive. Finally, factorial analysis allowed the determination of the effects of waxes on the rheological parameters of the formulations. A quantitative relationship between wax concentration and significant responses was established, permitting the prediction of desirable rheological properties for improved sunscreen efficacy. (AU)

FAPESP's process: 18/16523-6 - Development and comparative safety and clinical efficacy evaluation of organic, inorganic and associated sunscreen
Grantee:Vitória Tonini Porto Ferreira
Support type: Scholarships in Brazil - Master