Simultaneous quantification of 2-pyrrolidone-5- carboxylic acid (PCA), urocanic acid (UCA), and histidine (His) in the stratum corneum by HPLC-PDA

• Ano de defesa: 2024
• Autor(a) principal: Santos, Caroline Saur
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Estrato córneo; Fator de hidratação natural; HPLC-PDA
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/9/9139/tde-02082024-084809/

The skin is the largest organ of the human body and has the function of protecting the organism from the external environment. In the most superficial part of the skin lies the stratum corneum, which functions to prevent transepidermal water loss (TEWL) and assist in skin homeostasis. These functions are carried out by the presence of the Natural Moisturizing Factor (NMF), a combination of free amino acids and their derivatives, such as pyrrolidone carboxylic acid (PCA) and urocanic acid (UCA), associated with other components. Some studies demonstrate that low levels of NMF are often related to dry, scaly skin, psoriasis, and dermatitis, hence the importance of being able to quantify it more accurately. The determination and quantification of NMF components, using ex-vivo samples, have been used in recent years and are reported in the first chapter of this study. Chromatographic methods are highlighted due to their frequency of use. However, other methods have also shown satisfactory results in this type of analysis, such as Raman spectroscopy, electrophoresis, confocal spectroscopy, among others. In the second chapter, the development of a protocol for simultaneous quantification of PCA, UCA, and histidine by HPLC-PDA is presented. This chapter emphasizes the target population of the research, establishing the population that provides clearer and distinct responses to the HPLC-PDA analysis. Using an analytical procedure validated in accordance with AOAC guidelines, it was possible to conclude that the population that best responds to this study consists of individuals up to 35 years old, of all phototypes, preferably women.