The　effects　of　cations　and　pH　on　the　in　vitro　ibuprofen　release　from　dextran-poly(acrylic　acid)　copolymer　were　investigated　at　varying　pH　and　Na+　or　Ca2+　concentrations.　These　results　revealed　that　ibuprofen　release　was　strongly　depended　on　the　acidic　and　basic　environments,　in　which,　the　cumulative　amount　released　in　24　h　reached　up　to　87　%　at　pH　2.0　but　only　32　%　at　pH　7.4,　respectively,　demonstrating　a　good　pH-dependency.　However,　cations　in　release　solution　exerted　a　remarkable　influence　on　ibuprofen　release,　especially　in　the　acidic　media.　Meanwhile,　ibuprofen　release　rate　decreased　with　increasing　strength　of　Na+,　Ca2+　and　NaCl　concentration.　The　zeta　potential　profiles　and　particle　distributions　at　different　ionic　strengths　indicated　that　cations　strongly　influence　ibuprofen　release　performance,　through　surface　charge,　hydrogen-bonding,　and　electrostatic　interactions　in　and　between　the　polymer　and　ibuprofen.　These　results　suggested　that　Na+　and　Ca2+　strength　exerted　a　profound　influence　on　the　pH-sensitive　in　vitro　ibuprofen　release　from　the　dextranpoly(acrylic　acid)　copolymer.