Development of glycolic acid niosome for skin delivery

Abstract

Glycolic acid (GA) is popularly used in many cosmetic products as exfoliant and moisturizer. Unfortunately high glycolic acid concentration has high potential for skin irritation. The aim of this study was to prepare and characterize glycolic acid niosomes in order to increase skin delivery and reduce its irritation effect. For this purpose niosomes which contain of various classes of nonionic surfactant such as polyoxyethylene alkyl ethers (Brij®52 and Brij®76), sorbitan fatty acid esters (Span®20, Span®40, and Span®60), glyceryl distearate (GDS), and sucrose laurate ester (L-595®) were prepared by sonication method that was devoid of organic solvent. Characterization of GA niosomes was then performed. Morphology of vesicle was observed by optical and polarized light microscopy. Size and size distribution were characterized by dynamic light scattering. Entrapment of glycolic acid was evaluated by ultracentrifugation and HPLC method. Physical stability was investigated by the change of morphology, size and size distribution, entrapment, and pH in each formulation. Release of GA through cellulose acetate membrane and permeation of GA across newborn pig skin were studied using modified Franz diffusion cells. Furthermore, irritation potential of niosomes was investigated by sheep red blood cell test. The results revealed that niosomes completely formed spherical shape. Niosomal size and entrapment depended on niosomal compositions and surfactant structure. All niosomal formulations were physical stable within two months of storage at ambient temperature. The release of GA from some selected niosomal systems was sustained and followed the first order kinetics. The release rate constants depended on entrapment and thermodynamic state of bilayers. Most of niosomal formulations enhanced GA permeability across the skin based on surfactant structure and thermodynamic state of bilayers. Moreover, all GA niosomes much reduced irritation than that from aqueous solution and depended on niosomal compositions, surfactant structure, and thermodynamic state of bilayers. Consequently, the results of this study indicate that niosomes could be developed as topical delivery of water soluble substances such as glycolic acid for cosmetic uses.