Lactobionic acid (4-O-beta-galactopyranosyl-D-gluconic acid), a disaccharide formed from gluconic acid and galactose, has been established as a potent antioxidant well suited for use in solutions intended to preserve organs stored for transplantation.1,2 This polyhydroxy bionic acid is used as an excipient agent in some pharmaceutical products and has been the object of increasing interest and use in cosmetics and cosmeceuticals.3 It is included in skin care formulations for its strong humectant and antiaging effects.3,4 Lactobionic acid has been shown to suppress the synthesis of hydroxyl radicals by dint of iron-chelating activity and hinders the production of matrix metalloproteinases (MMPs), which promote photoaging.2,3,5 It may also present an advantage over the class of alpha-hydroxy acids used to treat photoaging by engendering less or no irritation, because of its larger molecular size and corresponding slower penetration rate.6 This column will focus on some recent research on the application of this strong antioxidant in dermatologic practice.
Lactobionic acid as an ingredient and vehicle
In 2010, Tasic-Kostov et al. compared the efficacy and irritation potential of lactobionic and glycolic acids (in gel and emulsion vehicles). In 77 healthy volunteers, the investigators found that alkyl polyglucoside (APG) , insofar as the former caused no irritation or skin barrier damage. In a second part to the study, they determined that efficacy of the acids was improved through the use of vehicles based on the natural emulsifier, . They concluded that lactobionic acid in a 6% concentration in an APG vehicle warranted consideration as a low-molecular option in cosmeceutical products.6
In a subsequent study, the same team found supportive evidence that APG-based emulsions are safe cosmetic/dermopharmaceutical vehicles and carriers for extremely acidic and hygroscopic AHAs, particularly lactobionic acid. They did note, however, that lactobionic acid markedly affected the colloidal structure of the emulsion and fostered the development of lamellar structures, which could influence water distribution within the cream. They concluded, therefore, that such an emulsion, which was stabilized by lamellar liquid crystalline structures, would not be a viable carrier for the hygroscopic actives to achieve optimal moisturizing potential.7More recently, Tasic-Kostov et al. investigated the antioxidant and moisturizing traits of lactobionic acid in solution as well as in a natural APG emulsifier–based system using 1,1-diphenyl-2-picrylhydrazyl free radical scavenging and lipid peroxidation inhibition assays. The researchers found that lactobionic acid exhibited suitable physical stability (though it exerted notable impact on the colloidal structure of the vehicle) as well as antioxidant activity in both formats, suggesting its application as a versatile cosmeceutical agent for treating photoaged skin.2
In 2017, Chaouat et al. found that lactobionic acid was a key component in a green microparticle carrier system for cosmetics also containing chitosan and linoleic acid (as the skin penetration–enhancing constituent). Chitosan and lactobionic acid made up the shell surrounding the linoleic acid core. The carrier system, in an aqueous solution, was found to be stable and able to encapsulate the hydrophobic skin lightener phenylethyl resorcinol.8