Ferulic acid-loaded aspasomes: A new approach to enhance the skin permeation, anti-aging and antioxidant effects

In this study, an innovative approach to enhance the skin permeation, anti-aging and antioxidant effects of ferulic acid (FA)-loaded aspasomal formulations were developed and evaluated in vitro and ex vivo. The chemical interactions between FA and excipients in the formulation were characterized by Differential scanning calorimetry (DSC) and Fourier-transformed infrared (FTIR). Aspasomes (ASPs) were produced using the film hydration method with different components and were evaluated according to in vitro characterization parameters (particle size (PS), polydispersity index (PDI), zeta potential (ZP), scanning electron microscopy (SEM), drug entrapment efficiency (EE%) and drug release profile), and the optimized formulation was determined. The 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to test the cytotoxicity of the ASPs and different FA solutions on the L929 cell line. In the stability studies, changes in characterization parameters and FA content of optimum ASPs stored in both suspended and lyophilized dry powder form in two different conditions over 3 months were monitored. Ex-vivo skin permeation study was done using mouse abdominal skin and the amount of penetrated FA was measured. Also, skin depth and density of blank and FA-loaded ASPs were evaluated by fluorescence microscopy. At the end of the permeation study, the antioxidant capacity of FA reaching the dermis layer and its inhibitory effect on collagenase and elastase enzymes were assessed. FTIR spectra and DSC thermograms assured chemical and physical compatibility. The selected optimum formulation (F2 coded) showed PS of 384 ± 1.52 nm, PDI of 0.015 ± 0.011, ZP of −39.2 ± 3.45 mV, EE of 58 ± 2.01% and drug release of 77.3 ± 0.554% and was used for permeation study. The lyophilized ASPs were physically stable, and the FA content of ASPs did not decrease significantly during 3 months of storage at 4 °C. The skin permeation experimental results indicated positive results that successfully developed FA-loaded ASPs have an effective FA permeability rate and better antioxidant and anti-aging effects than the free drug and are useful and effective for improving skin permeation and slowing skin aging with topical applications.