Open AccessElectrohydrodynamic spray applicator for homogenous application and reduced overspray of sunscreen
Author(s) -
Schleusener Johannes,
Schanzer Sabine,
Wille Charlotte,
Langen Valentin,
Richter Heike,
Lademann Jürgen,
Meinke Martina C.
Publication year - 2021
Publication title -
skin research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.521
H-Index - 69
eISSN - 1600-0846
pISSN - 0909-752X
DOI - 10.1111/srt.12924
Subject(s) - homogeneity (statistics) , materials science , aerosol , biomedical engineering , analytical chemistry (journal) , chemistry , chromatography , mathematics , medicine , statistics , organic chemistry
Abstract Background The recommended amount of sunscreen by hand application (2 mg/cm 2 ) is in reality not achieved, which decreases the homogeneity and thereby the effective sun protection factor (SPF). Materials and Methods The homogeneity of sunscreen applied by a newly developed spray applicator using an electrostatically charged aerosol, for which a hand rubbing of the formulation is not necessary, is evaluated. In vivo experiments were performed on the volar forearms of human volunteers using the spray applicator compared to the standardized hand application according to ISO 24444. Results The distribution homogeneity was assessed qualitatively using in vivo laser scanning microscopy and quantitatively by absorption spectroscopy after tape stripping and by the standard deviation of multiple spatially displaced reflectance measurements for non‐invasive SPF determination below the minimal erythemal dose, which showed a significantly higher homogeneity by 20.9% after spray application compared to hand application. Conclusion Non‐invasive SPF determination of multiple spatially displaced reflectance measurements was proven to be a suitable method for the non‐invasive determination of the sunscreen distribution homogeneity. Electrostatically charged spray application increased the sunscreen distribution homogeneity on the skin and can reduce the amount of overspray.