Poly(hydroxyethyl methacrylate)-based co-polymeric hydrogels for transdermal delivery of salbutamol sulphate

Various co-polymeric hydrogels for transdermal delivery of salbutamol sulphate were synthesized using 2-hydroxyethyl methacrylate (HEMA), methacrylic acid (MAA) and N-[3-(dimethylamino) propyl] methacrylamide (DMAPMA) in the presence of ammonium persulphate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED) as redox free radical initiator and ethyleneglycol dimethacrylate (EGDMA) as a cross-linker. The synthesized co-polymeric hydrogels were characterized using FT-IR spectral studies and swelling studies. It was observed that percentage swelling of co-polymeric hydrogel increased with the increasing concentration of DMAPMA and methacrylic acid. Salbutamol sulphate, a well-known vasodilator, was labeled with Tc-99m (technetium) and loaded on circular discs of various hydrogels. In vitro permeation of radiolabelled salbutamol sulphate was carried out using a Franz diffusion cell in phosphate-buffered saline (PBS, pH 7.4) as dissolution medium through mice skin. It was observed that drug release from the co-polymeric hydrogel carriers increased on increasing the amount of DMAPMA in the polymeric carriers, while it decreased on increasing the amount of MAA content. The local toxicity studies of DMAPMA-containing hydrogel patches were carried out in rabbits. Drug-loaded patches applied on rabbit skin showed no toxicity, even after 1 week of studies.