Fabrication, characterization and transdermal properties of double cross-linked gel beads with 4-n-butylresorcinol

In this paper, sodium alginate (SA) -agarose double cross-linked gel beads were prepared to improve the solubility of 4-n-butylresorcinol and to reduce skin irritation. The wrappage material suitable for 4-nBR gel beads was SA-agarose double cross-linking material, and the internal inclusions were in the form of 4-n-butylresorcinol nanoemulsions (4-nBR NEs). Under the orthogonal fluorescence microscope, it was observed that the gel beads were spherical in shape, with smooth and rounded surfaces and permeable interiors. The encapsulation rate of the gel beads was 84.37 ± 3.56 %, and the average diameter was 1.93 ± 0.21 mm. Scanning electron microscopy showed that the gel beads were spherical in shape. The cumulative leakage rate of the gel beads on the 35 th day was 4.72 ± 0.06 %, suggesting that the gel beads encapsulated 4-butylresorcinol to good effect and with high stability. This proves that the gel beads wrapped with 4-nBR are highly effective and stable. In vitro skin permeability assessment verified the good skin permeability of nanoemulsions (NEs).