Fe (III)-Coordinated N-[Tris(Hydroxymethyl)Methyl]Acrylamide Modified Acrylic Pressure-Sensitive Adhesives with Enhanced Adhesion and Cohesion for Efficient Transdermal Application

Pressure-sensitive adhesives are critical to the product's safety, efficacy, and quality in transdermal drug delivery systems. However, many defects of transdermal patches (e.g., insufficient adhesion, patch dis-placement, and "dark ring" phenomenon) remain. Herein, the N-[tris(hydroxymethyl)methyl]acrylamide (NAT)-modified acrylic pressure-sensitive adhesive coordinated with Fe(III) (AA-NAT/Fe3 +) was creatively proposed. Results demonstrated that the adhesiveness and cohesiveness of the optimized AA-NAT/Fe3 + were higher by 1.8-and 9.7-fold, respectively, than those of commercially available DURO-TAK (R) 87-4098 due to the hydrogen bonding interaction of NAT-skin interface and coordination of NAT-Fe3 +. Moreover, compared with that of DURO-TAK (R) 87-4098, the adhesion time of AA-NAT/Fe3 + on the human forearm was remarkably prolonged, and no "dark ring" phenomenon was observed for AA-NAT/Fe3 + after removal. After clonidine (CLO) was loaded into AA-NAT/Fe3 +, controlled drug release and a drug transdermal be-havior were endowed for CLO@AA-NAT/Fe3 + in vitro and in vivo . AA-NAT/Fe3 + still maintained superiority in adhesion and cohesion properties after CLO loading. These observations would contribute to the devel-opment of pressure-sensitive adhesives with outstanding adhesion and cohesion for transdermal patches. Statement of significance This N-[tris(hydroxymethyl)methyl]acrylamide-modified acrylic pressure-sensitive adhesive coordinated with Fe(III) has enhanced adhesion and cohesion properties, which provide a simple but effective strat-egy to solve the problems (e.g., insufficient adhesion, patch displacement, and "dark ring" phenomenon) in existing transdermal patches.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.