Reduction of enlarged facial pore using ion-paired amino acid through enhancement in skin permeation and exfoliation: A placebo-controlled in vivo study.

Abstract

Serine is a hypoallergenic but inefficient chemical exfoliant. Serine paired with arginine (ion-paired amino acid, IPA) shows enhanced lipophilicity, skin permeation, and exfoliation efficacy. This study was conducted to determine whether exfoliation using an emulsion containing IPA could reduce enlarged facial pores and improve the dermis density. IPA formation was validated by spectroscopic analysis. Enhanced permeability and exfoliation efficacy were evaluated ex vivo using porcine skin. In a clinical trial, healthy Korean women aged 20-49years (mean age±SD: 35.6±8.6, n=64) were evaluated, and the right and left sides of the cheeks were randomly chosen. An emulsion containing 4.0% IPA and placebo emulsion were applied to each side for 6weeks. To evaluate pore sizes following treatment, the number of enlarged facial pores, inner skin structures from the stratum corneum to epidermal-dermal interface, and dermal density on each cheek of the participants were assessed. IPA showed a significantly increased partition coefficient in n-octanol-water. In porcine skin, permeation of serine after 12hour was 70% higher for the IPA than for serine alone at the same percent weight concentrations. In the clinical trial, after 6weeks, the number of enlarged facial pores was changed by -19.317% in the IPA emulsion group (P<.001) and -2.930% in placebo emulsion group (P=.254). Exfoliation with an IPA-containing emulsion reduced enlarged facial pores and increased the dermis density. IPA, effective mild exfoliator, can be used as a major ingredient for the cosmeceutical skincare products in the future.