Study of the Migration of Small Molecules Through the Hair Fiber to the Scalp.

Author: Angela Cristina Vargas Calle*; Ana Raquel Zeferino; Gustavo Facchini; Samara Eberlin; Barbara de Freitas Carli; Adriano Pinheiro. 

Published at: January 01, 2024

https://kosmoscience.com/pdf/study-of-the-migration-of-small-molecules-through-the-hair-fiber-to-the-scalp.pdf

Abstract Human hair is a mainly keratin structure that packages itself in a highly complex way. This high complexity leaves free spaces (vacancies) that allow substances to permeate the hair fiber. The permeation is influenced by different factors including pH of the environment, hair porosity, and quality of the hair. The study of the permeation of molecules through the hair fiber to the scalp is important for the development of cosmetic products with actives that could potentially have efficacy no just on the fiber but on the scalp. On this study scalp explants from rhytidectomy with hair shafts of 6 cm were cut in pieces with 6mm diameter. The hair tips were submersed in an aqueous solution of fluorescent dye eosin at 3 different times. After that, the skin explants were included on TOC compound and cut with cryotome. The cuts were analyzed by fluorescence microscopy to understand if the dye was able to migrates to the scalp. The results show migration of the fluorescent dye in all the times tested. The presence of fluorescent molecules on the skin cuts means that the actives absorbed on hair fiber are capable of achieving the hair bulb and in contact time higher than 30 min they can even reach the inner structures of the scalp. Keywords: Hair Permeation, pH, Hair Porosity, Hair Evaluation, Scalp.