Microneedling-enhanced kojic acid serum: A comprehensive study of retention, permeation, dermal targeting, and cytotoxicity

Abstract

Melasma is a chronic hyperpigmentation disorder primarily affecting sun-exposed facial areas, and kojic acid, a tyrosinase inhibitor, has shown promise in its management. This study evaluated the efficacy of a 2.0 % kojic acid serum (SKA2) combined with microneedling for Melasma treatment, comparing two microneedling devices: a roller and an electric pen.

The serum's stability, microbiological safety, and cytotoxicity assays were evaluated. Furthermore, ex vivo permeation and retention were analyzed using porcine ear skin and a twocompartment diffusion system. Results demonstrated that SKA2 exhibited the expected characteristics for kojic acid delivery. The samples evaluated showed good microbiological stability with no coliforms, S. aureus, or P. aeruginosa, and the count of colonies of microorganisms, molds, and yeasts was <10 CFU/mL. Permeation assays revealed that microneedling significantly enhanced kojic acid delivery to the receptor fluid (p < 0.05). Among the microneedling devices, the 0.5 mm roller showed the most effective retention of kojic acid in the skin, even though no significant difference was observed between tests on microneedling skin (p < 0.05). No cytotoxic effects on keratinocytes or fibroblasts were demonstrated (cell viability >70 %). Even though KA permeation occurs, its use in association with MN is considered safe.

In conclusion, MNappears to be promising in promoting the retention ofKAin the cutaneous strata, although no significant difference has been demonstrated between the devices used in different needle lengths, meaning that both rollers and electric pens can be used in association with SKA2 in the treatment of melasma.