Enhanced vitamin C skin permeation from supramolecular hydrogels, illustrated using in situ ToF-SIMS 3D chemical profiling

Abstract

Vitamin C (ascorbic acid) is a naturally occurring, powerful anti-oxidant with the potential to deliver numerous benefits to the skin when applied topically. However, topical use of this compound is currently restricted by an instability in traditional formulations and the delivery and eventual fate of precursor compounds has been largely unexplored. Time of flight secondary ion mass spectrometry (ToF-SIMS) is an emerging technique in the field of skin research and offers detailed chemical analysis, with high mass and spatial resolution, as well as profiling capabilities that allow analysis as a function of sample depth. This work demonstrates the successful use of ToF-SIMS to obtain, in situ, accurate 3D permeation profiles of both ascorbic acid and a popular precursor, ascorbyl glucoside, from ex vivo porcine skin. The significant permeation enhancing effect of a supramolecular gel formulation, produced from an amphiphilic gemini imidazolium-based surfactant, was also demonstrated for both compounds. Using ToF-SIMS, it was also possible to detect and track the breakdown of ascorbyl glucoside into ascorbic acid, elucidating the ability of the hydrogel formulation to preserve this important conversion until the targeted epidermal layer has been reached. This work demonstrates the potential of ToF-SIMS to provide 3D permeation profiles collected in situ from ex vivo tissue samples, offering detailed analysis on compound localisation and degradation. This type of analysis has significant advantages in the area of skin permeation, but can also be readily translated to other tissue types.

Protein identification by 3D OrbiSIMS to facilitate in situ imaging and depth profiling

“…Sequences characteristic to these proteins were manually assigned in situ in the skin layers where they are known to be present exclusively or predominantly. The layers of the skin in the depth profile, specifically the stratum corneum, underlying epidermis and dermis, were assigned based on the abundance of a phospholipid marker (PO 3 − ), as described in previous analysis of skin in SIMS by Starr et al 32 (Fig. 2c).…”

Stabilization of vitamin C in emulsions of liquid crystalline structures

“…Derivatives of Vit C, such as sodium ascorbyl phosphate, magnesium ascorbyl phosphate, sodium ascorbate and ascorbyl-6-palmitate have been employed in cosmetic and pharmaceutical formulations in order to remedy this problem [Segall and Moyano, 2008;Serrano et al, 2015]. However, despite being more stable, their permeation efficiencies and biological activities are still limited [Stamford, 2012;Starr et al, 2019;Caritá et al, 2020]. Results disclosed in patents also show limited stabilization effects of anhydrous formulations [Thomas, 2014].…”

Experimental and Data Analysis Considerations for Three-Dimensional Mass Spectrometry Imaging in Biomedical Research

“…Supramolecular hydrogels and their capability to enhance skin permeation of vitamin C (ascorbic acid) and its precursor (ascorbyl glucoside) have also been investigated with 3D-SIMS of ex vivo porcine skin [40]. Researchers demonstrated that the hydrogel enhances skin permeation of both compounds and preserves the conversion of the precursor into vitamin c until it reaches the epidermal layer, the intended target ( Fig.…”

“…The results showed a deeper permeation when a hydrogel is used. This article was published in[40] (copyright Elsevier). b Quantitative 3D MALDI-MSI of the anti-cancer drug paclitaxel in a malignant pleural mesothelioma tumor.…”