Grafting pH-sensitive poly[2-(diethylamino)ethyl methacrylate] modification of vesicular silica with activator regenerated by electron transfer atom transfer radical polymerisation for controlled drug release

pH-sensitive poly[2-(diethylamino)ethyl methacrylate]-modified vesicular silica (VS-PDEAEMA) is prepared in different amounts of 2-(diethylamino)ethyl methacrylate via activators regenerated by electron transfer for atom transfer radical polymerisation. The pH-responsive polymer is successfully grafted onto the shell of vesicular silica (VS) and then characterised. The inner PDEAEMA layer became thick, while the outmost polymer thickness did not change as the monomer amount was increased. Pure VS and VS-PDEAEMA are employed as supports for the loading and release of captopril. The release profiles of the captopril-loaded samples are studied in phosphate buffer solution with different pH values (4.0, 6.0 and 7.4). The captopril release rate can be controlled by PDEAEMA-functionalised carriers. Moreover, 31.5 and 70.0 wt% of captopril is released from the grafted polymer at pH 7.4 and 4.0, respectively. The modified VS can have potential applications in targeted drug delivery systems.