Preparation of gelatin/epigallocatechin gallate self-assembly nanoparticles for transdermal drug delivery

Abstract

Atopic dermatitis (AD) is a relatively common inflammatory skin disease identified by swollen, cracked or inflamed skin. Currently, the primary treatments for AD are corticosteroids. However, after prolonged usage, corticosteroids have the potential to produce severe side effects. Epigallocatechin gallate (EGCG), a compound found in tea, provides anti-inflammatory properties that offer a potential alternative to corticosteroids in treating AD. However, the delivery method of EGCG greatly affects its bioavailability. The skin’s barrier makes it hard to delivery EGCG directly through intact skin. Nanoparticles provide an intriguing option for atopic transdermal delivery of EGCG due to their biochemical properties and ease of application. In this study, biodegradable self-assembling gelatin/EGCG nanoparticles (GE NPs) were synthesized for AD treatment. GE NPs had a spherical morphology with an average diameter of 112 nm and a zeta potential of nearly 23 mV. Cell viability assays indicated 10 μg/mL concentrations of EGCG or GE were non-toxic to human dermal fibroblast (WS1) cells. Intracellular quantification of dye conjugated GE was proceeded, and it revealed high amounts of fluorescence dye in cells. Lipopolysaccharide-inflamed WS1 cells were treated with EGCG solution or GE NPs, and IL-6 and IL-8 cytokine expression was assessed by ELISA method. GE NPs decreased inflammation as demonstrated by reducing IL-6 and IL-8 expression in WS1 cells in vitro with EGCG concentrations as low as 1 μg/mL. The topical delivery of GE NPs in vivo was examined by dropping different formulations on nude mice skin. GE NPs demonstrate greater skin absorbance than free EGCG in vivo and without eliciting adverse effects. This approach provides a novel alternative potential treatment for skin inflammatory diseases.