Writing in Cosmetic Dermatology, researchers from Beijing’s Technology and Business University investigated worldwide knowledge about cosmetic skin delivery and evaluation methods – analysing the literature over the past few decades, between 1985 and 2020.
Active cosmetic delivery systems and efficacy evaluation
Findings outlined “various methods” available for industry to enhance cosmetic ingredient penetration and permeation into and through specific skin layers or structures, including chemical enhancement techniques like solvents or surfactants; physical enhancement via microneedles or lasers; and use of nanotechnologies, biochemicals and natural penetration enhancers. And there were many more “novel permeation enhancement technologies” on the horizon, the researchers wrote in the review.
There was also a plethora of evaluation techniques being used to assess cosmetic ingredient delivery, they said, including the diffusion cell model; mathematical models; 3D skin models; mass spectrometry imaging; and use of the Raman spectrum. The issue here, however, was that there were “no unified domestic and international laws and regulations about evaluation of transdermal delivery,” they said.
At present, countries worldwide all had "similar but not identical" regulations in place on cosmetic ingredient delivery.
“…We can enhance penetration with the help of a variety of techniques, but the consideration of enhancing the effect also brings the concern of over-deep penetration. No entry into the bloodstream is the most essential requirement for cosmetics. Therefore, it is necessary to formulate unified laws and regulations to regulate behaviour. Besides, the increasing number of evaluation methods also requires a balanced consideration of the applicability of each evaluation method.”
The future? ‘Common standards’ and ‘multidimensional regulations’ required
The researchers said future innovation in cosmetic skin delivery would likely see a combination of beauty equipment and technologies used, particularly for skin repair, with many future advances set to be “very promising”.
“Some trends in the future include improved permeation systems that release active substances by regulating pH and temperature. How to release the active components at specific sites more accurately, how to control the release time and concentration of active components, and how to take the initiative to produce osmotic behaviour instead of relying solely on biological passive diffusion will be the main research objectives of cosmetic delivery systems in the future,” they wrote.
And as these methods and techniques advanced, the researchers said it would be vital “further basic research” about delivery systems, the diffusion of active ingredients and how they impacted penetration would be key. Only with a “thorough understanding of the skin” could industry develop “safer, more stable techniques” that promoted penetration, they said.
International alignment on such advances would therefore become increasingly important, the researchers wrote.
“The legal and regulatory issues that come along with the rise of various penetration promotion technologies also require the efforts of various countries to jointly launch a set of common standards and multidimensional regulations in regards to penetration issues with a variety of evaluation and assessment methods,” they wrote.
“Cosmetics manufacturers should also pay attention to the percutaneous penetration problem. The safety and stability of raw materials must be the premise.”
Source: Cosmetic Dermatology
Published online ahead of print, doi: 10.111/jocd.14037
Title: “A review of cosmetic skin delivery”
Authors: X. Hu and H. He
