Helvoet Pharma N.v.

Rik Schrooten

A lyophilization stopper made of a rubber elastic material is composed of a shank (1) and a circular disc shaped flange (2) made in one piece with the shank. The shank includes a cavity (4) which surrounds the longitudinal axis (A) of the shank and is open toward the free end face (3) of the shank, while extending toward a central closed wall portion (2b) of the flange. A first section (Z.sub.1) of the shank disposed between a first transverse plane (Q.sub.1) and a second transverse plane (Q.sub.2) has a closed outer circumferential face which has a maximum diameter (D). A subsequent second section (Z.sub.2) includes a passage which communicates with the cavity as well as a plurality of projecting blocking elements (14a-14c). The inner wall surface (19) which laterally delimits the cavity (4) and has an increasing diameter with increasing approach to the free shank end face lies completely outside a cone (K) whose axis is the longitudinal axis (A) of the shank, whose tip (K.sub.1) lies in the transverse plane (Q.sub.1) and whose tip angle (.beta.), in degrees, is larger than a value calculated according to the formula

Growing community of inventors

Kleine Brogel, Belgium

Rik Schrooten