In vitro skin permeation/retention of daidzein, genistein and glycitein from a soybean isoflavone rich fraction-loaded nanoemulsions and derived hydrogels

摘要

Positive skin effects have been reported for isoflavones, mainly for their aglycone forms. In this way, the present study addresses the development of products containing isoflavone aglycone-rich fraction (IAF) aimed for dermal application. The formulations investigated were IAF nanoemulsions (NEIAF) and derivative semisolid hydrogels composed of hyaluronic acid (H-NEIAF). The IAF used during this study contained high purity of isoflavone aglycones (IA), obtained after purification of a soybean extract previously hydrolyzed by an enzymatic process. Nanoemulsions (NE) containing 1.0 mg of IA/mL (expressed as sum of genistein, daidzein and glycitein) were prepared, and, in some formulations, hyaluronic acid (3%) was added to obtain hydrogels. Formulations exhibited mean droplet size below to 300 nm and negative zeta-potential. A significant decrease of IA release from formulations was observed when compared to a control (control > NEIAF > HNEIAF). Moreover, after 8 h of permeation/retention in vitro study with porcine ear skin, a significant increase of IA retention was observed from formulations. The distribution of IA in skin layers was evaluated, and the highest IA retention was found in dermis. These results demonstrate the potential of both formulations for topical IA skin applications.