Formulation and in vitro penetration study of recombinant human epidermal growth factor-loaded transfersomal emulgel

Purpose: Recombinant human epidermal growth factor (rhEGF) is a 6045-Da peptide that promotes the cell growth process, and it is also used for cosmetic purposes as an anti-aging compound. However, its penetration into skin is limited by its large molecular size. This study aimed to prepare rhEGF-loaded transfersomal emulgel with enhanced skin penetration compared with that of non-transfersomal rhEGF emulgel. Methods: Three transfersome formulations were prepared with different ratios between the lipid vesicle (phospholipid and surfactant) and rhEGF (200:1, 133:1, and 100:1) using a thin-film hydration-extrusion method. The physicochemical properties of these transfersomes and the percutaneous delivery of the transfersomal emulgel were evaluated. Long-term and accelerated stability studies were also conducted. Results: The 200:1 ratio of lipid to drug was optimal for rhEGF-loaded transfersomes, which had a particle size of 128.1 ± 0.66 nm, polydispersity index of 0.109 ± 0.004, zeta potential of −43.1 ± 1.07 mV, deformability index of 1.254 ± 0.02, and entrapment efficiency of 97.77% ± 0.09%. Transmission electron microscopy revealed that the transfersomes had spherical and unilamellar vesicles. The skin penetration of rhEGF was enhanced by as much as 5.56 fold by transfersomal emulgel compared with that of non-transfersomal emulgel. The stability study illustrated that the rhEGF levels after 3 months were 84.96-105.73 and 54.45%-66.13% at storage conditions of 2°C-8°C and 25°C ± 2°C/RH 60% ± 5%, respectively. Conclusion: The emulgel preparation containing transfersomes enhanced rhEGF penetration into the skin, and skin penetration was improved by increasing the lipid content.