English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Para-phenylenediamine (PPD) is a chemical that is widely used in hair dyes. Multiple safety and regulatory agencies have categorized PPD as a potent sensitizer. In addition, PPD has carcinogenicity and genotoxicity attributes and, consequently, it is regulated at a maximal concentration of 2.0%. The aim of this study was to test whether the limit for PPD is surplus, and hence whether the consumer may be exposed to unnecessarily PPD levels. Experimentally, the analysis of PPD was performed using HPLC, where method validation and an inter-laboratory comparison test (ILC) were conducted to evaluate method performance. Thirty-three commercial products were analyzed, and five products were chosen to study the unconsumed PPD. Successfully, the implemented method confirmed its suitability and validity for the determination of PPD. For ILC results, PPD levels were 0.97 ± 0.04% and 0.92 ± 0.02%, quantified by our laboratory and an accredited laboratory, respectively. For all products, the initial concentration (T0) of PPD was lower than the regulatory limit. After 45 min, the content of PPD significantly reduced compared to T0. One product showed unconsumed PPD to be as high as 96% following the recommended dyeing time. In conclusion, the existence of high levels of unreacted PPD increases the likelihood of allergic events and elevates the risk of PPD-related chemicals. Collaborative efforts between industries, regulatory bodies, and health-related decision makers are deemed necessary to establish safe concentrations for PPD.

Study of P-Phenylenediamine (PPD) Concentrations after Hair Dye Mixing: A Call for Safety Reassessment