Mechanism of action of a lipophilic derivative of salicylic acid on normal skin

Characterizing the nanomechanical properties of microcomedones after treatment with sodium salicylate ex vivo using atomic force microscopy

OBJECTIVE

The treatment of acne presents a major clinical and dermatological challenge. Investigating the nanomechanical properties of the microcomedone precursor lesions using atomic force microscopy (AFM) may prove beneficial in understanding their softening, dissolution and prevention. Although the exact biochemical mechanism of NaSal on microcomedones is not fully understood at present, it appears to exhibit a significant exfoliation effect on the skin via corneodesmosome dissolution.

METHODS

Therefore, to support this exploration, sodium salicylate (NaSal), a common ingredient employed in skin care products, is applied ex vivo to microcomedones,collected by nose strip adhesive tape, and their nanomechanical properties are assessed using AFM. Although the exact biochemical mechanism of NaSal on microcomedones is not fully understood at present, it appears to exhibit a significant exfoliation effect on the skin via corneodesmosome dissolution.

RESULTS

Herein, our findings demonstrate that when microcomedones are treated with 2% NaSal, samples appeared significantly more compliant ('softer') ((1.3 ± 0.62) MPa) when compared to their pre-treated measurements ((7.2 ± 3.6) MPa; p = 0.038). Furthermore, elastic modulus maps showed that after 2% NaSal treatment, areas in the microcomedone appeared softer and swollen in some, but not in all areas, further proving the valuable impact of 2% NaSal solution in altering the biomechanical properties and morphologies in microcomedones.

CONCLUSION

Our results are the first of their kind to provide qualitative and quantitative mechanobiological evidence that 2% NaSal decreases the elastic modulus of microcomedones. Therefore, this study provides evidence that NaSal can be beneficial as an active ingredient in topical treatments aimed at targeting microcomedones.

The use of hydroxy acids on the skin: characteristics of C8-lipohydroxy acid

The hydroxy acids are widely used in skin creams because of their exfoliating and rejuvenating effect on photoaged skin. As a member of this family, the salicylic acid derivative known in the literature as 2-hydroxy-5-octanoyl benzoic acid or beta-lipohydroxy acid has also been proposed as an exfoliant and as a treatment of photoaged skin and acne. This article reviews the effects of the hydroxy acids and compares them to those of the salicylic acid derivative. We propose the name C(8)-lipohydroxy acid (C8-LHA) for this derivative to differentiate it from other related compounds. The lipophilic nature of C8-LHA and its relatively slow penetration in the skin afford it an exfoliating effect that is efficient at low concentrations. It appears to have antimicrobial, anti-inflammatory, and anticomedogenic properties, which make it effective against acne. Its antifungal and exfoliating properties are also likely to prove useful in combating dandruff.