Drug permeability of modified silicone polymers. III. Hydrophilic pressure-sensitive adhesives for transdermal controlled drug release applications

A new class of hydrophilic silicone/organic pressure-sensitive adhesives (PSAs) was formulated from polydimethylsiloxane-poly(ethylene oxide) graft copolymers and silicone resins. The following effects of the structure of the graft copolymers and silicone resins on the adhesion and the drug permeability were investigated: (a) the size and the degree of the grafting, (b) the degree of polymerization of the polysiloxane and (c) the loading level and molecular weight of the silicone resin. It was demonstrated that a number of therapeutic agents could be incorporated into the PSAs without compromising their functional adhesive tape properties. The PSAs not only had excellent drug permeabilities but also retained their adhesion upon aging, thus permitting their use in transdermal controlled drug release applications. This family of PSAs has a distinct advantage over other PSAs because it also enhanced the release rates of hydrophilic drugs.