Comparative study of glycolic acid peeling vs. vitamin C-iontophoresis in Melasma

Abstract

Background: Glycolic acid has become popular and could provide an alternative choice to the current depigmenting agent. Vitamin C has been known as strong reducing agent and is supposed to retard synthesis of melanin pigment. Iontophoresis is emerging technologies capable of enhancing drug penetration through stratum corneum. Iontophoretic drug delivery may be easier following the chemical enhancer pretreatment. Objective: We evaluated the efficacy of vitamin C-iontophoresis and glycolic acid peeling for melasma. Methods: 34 patients with facial melasma were treated with 30% glycolic acid peeling or vitamin C-iontophoresis or 30% glycolic acid peeling combined with vitamin C-iontophoresis. The treatment was performed weekly for a period of 12 weeks. Iontophoresis was performed for 6 minutes under a constant direct current of 0.3-1.0 mA/cm2. The exposure time for glycolic acid were 2 minutes. Before and after 12 weeks treatment, the state of melasma was documented using by the modified version of Melasma Area and Severity Index(mMASI) and Mexameter MX16®. We also measured vitamin C2-phosphate flux by in vitro iontophoresor and HPLC assay. Results: The mean scores of both mMASI and Mexameter MX16® after 12-week treatment were lower than those of baseline in all groups(p<0.05). Increasing vitamin C2-Phosphate concentration and increasing current density correlated with larger flux, and the flux in the first 40 minutes of the experiment appeared to be constantly larger than the steady-state flux during the period of the rest of the experiment, regardless of the current density. Pretreatment by peeling with glycolic acid did not significantly affect the vitamin C2-Phosphate flux through normal skin in vitro. Conclusion: Pretreatment by peeling with glycolic acid did not have a major impact on the vitamin C2-Phosphate flux in melasma patient.