Enhancing Skin Permeation of Nanoemulsions through Associative Polymeric Micelles-Mediated Drop-to-Skin Dipolar Interactions

Abstract This study presents a facile but useful methodology to improve the skin permeation of nanoemulsions through associative polymeric micelle (APM)-mediated drop-to-skin dipolar interactions. Amphiphilic triblock copolymers, poly(ethylene oxide)-b-poly(e-caprolactone)-b-poly(ethylene oxide) (PEO-PCL-PEO), were co-assembled with lecithin to fabricate APMs. As model drug carriers, nanoemulsions were prepared using the same amphiphile composition. Dense-suspension rheological studies revealed that when APMs co-existed with nanoemulsions, the drop-to-drop association was predominantly influenced by the PEO chain conformation surrounding the APMs; shorter PEO chains reduced the APM-mediated nanoemulsion association due to weak chain conformation. The shorter PEO chains of the APMs promoted the drop-to-skin association. Therefore, APMs with short PEO chains aided the penetration of the nanoemulsion into the skin. These results highlight that manipulation of the nanoemulsion drop association is important and plays a role in enhancing dermal drug delivery performance.