Ascorbic acid and its hydrophilic derivatives in commercial cosmetics : a cross-sectional study of their quality control and stability

Temova Rakuša, Žane (author), Roškar, Robert (author)

Ascorbic acid and its hydrophilic derivatives, ascorbyl phosphate, ascorbyl glucoside, and 3-O-ethyl ascorbic acid, are wide used active ingredients in cosmetics, with concentrations increasingly declared on product labels. Since such products are not subject to routine quality control, this study aimed to evaluate the content-related quality and stability of a comprehensive sample of commercial cosmetics. For this purpose, a selective HPLC-UV analytical method for their simultaneous determination was developed, validated, and applied to 41 products. The analysis revealed 0–31.7% (m/m) contents and inappropriate labeling in 22% of the products, including the absence and replacement of the labeled vitamin C form. Over half (57%) of the determined contents corresponded to the labels, which was claimed for 31 products, while the remaining contents were considerably lower (<80%). The stability study, performed on selected cosmetics and standard solutions under ambient and elevated temperatures, demonstrated instability, which could account for their inadequate content. Thus, the instability was found to be temperature-dependent and most pronounced for ascorbic acid, whereas the product price did not show a clear correlation with greater content or stability. Overall, these results highlight the need for proper quality control and stricter cosmetics regulation as well as formulation design to achieve sufficient stabilization, as observed in certain products.

• Language: English
• Keywords: 3-O-ethyl ascorbic acid, active ingredients, ascorbic acid, ascorbyl glucoside, ascorbyl phosphate, content, HPLC-UV, labeling, stability indicating method, stability testing
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FFA - Faculty of Pharmacy
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 23 str.
• Numbering: Vol. 13, iss. 4, art. no.195
• PID: 20.500.12556/RUL-185588
• UDC: 687.5.05+665.58
• ISSN on article: 2079-9284
• DOI: 10.3390/cosmetics13040195
• COBISS.SI-ID: 287443459
• Publication date in RUL: 11.08.2026

Record is a part of a journal

• Title: Cosmetics
• Shortened title: Cosmetics
• Publisher: MDPI AG
• ISSN: 2079-9284
• COBISS.SI-ID: 523046937

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: 3-O-etil askorbinska kislina, aktivne sestavine, askorbinska kislina, askorbil glukozid, askorbil fosfati, vsebnost, HPLC-UV, označevanje, metoda za določanje stabilnosti, testiranje stabilnosti, kozmetični izdelki, kozmetika

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P1-0189
• Name: Farmacevtska tehnologija: od dostavnih sistemov učinkovin do terapijskih izidov zdravil pri otrocih in starostnikih