초록 ▼

A swellable cannula is formed of concentric inner and outer hydrophilic and substantially non-hydrophilic layer structures. The hydrophilic layer structure comprises at least 2/3rds of the cross-sectional area of the wall of the cannula. The substantially non-hydrophilic layer structure is either su

A swellable cannula is formed of concentric inner and outer hydrophilic and substantially non-hydrophilic layer structures. The hydrophilic layer structure comprises at least 2/3rds of the cross-sectional area of the wall of the cannula. The substantially non-hydrophilic layer structure is either substantially water impermeable or allows water to pass through at a controlled rate. The substantially non-hydrophilic layer structure may also control the diffusion of medicaments. The cannula has controlled softenability and swellability characteristics.

대표청구항 ▼

A swelling multilayer cannula having proximal and distal end portions and a wall defining an inner lumen, comprising: (a) a hydrophilic layer structure having one or more hydrophilic layers having respective outer and inner surfaces and being formulated of a hydrophilic material characterized in tha

A swelling multilayer cannula having proximal and distal end portions and a wall defining an inner lumen, comprising: (a) a hydrophilic layer structure having one or more hydrophilic layers having respective outer and inner surfaces and being formulated of a hydrophilic material characterized in that it increases in volume more than 1.3:1 upon contact with an aqueous medium at 37°C., said hydrophilic layer structure comprising at least ⅔rds of the cross-sectional area of said wall, said inner lumen swelling such that its cross-sectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°C.; and (b) a substantially non-hydrophilic layer structure having one or more substantially non-hydrophilic layers having respective outer and inner surfaces and being formulated of a substantially non-hydrophilic material, an outer or inner surface of each of said hydrophilic layers being bonded to a corresponding inner or outer surface of at least one of said substantially non-hydrophilic layers, said bonded hydrophilic and substantially non-hydrophilic layers being of a construction such that they remain bonded to one another following swelling of said lumen such that its cross-sectional area increases more than 20% upon contact of said hydrophilic layer structure with said aqueous medium at 37°C.