US 5,472,422 AGranted

Dual-chamber injection cartridge

AssigneePharmacia Aktiebolag

InventorOlle Ljungquist

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Abstract

A method for manufacturing an injectable preparation of a pharmaceutically active agent suitable for storage in a dual-chamber injection cartridge. A dual chamber injection cartridge is provided, including: a barrel; a front chamber for a solid component; a rear chamber for a liquid component; a displaceable front piston separating the front and rear chambers; a closure sealing the front end of the barrel; and a constriction between the front and rear ends of the barrel. The constriction has a non-circular cross-section and an openable bypass connection permitting passage of liquid between the rear and front chambers. Prior to opening the bypass connection, the front piston is positioned between the constriction and the rear end of the barrel. The constriction resists displacement of the front piston in a direction of the front end of the barrel when the piston is in the vicinity of the constriction. The constriction prevents displacement of the front piston toward the front end of the barrel when a vacuum exists in the front chamber. A pressure in the vicinity of atmospheric pressure exists in the rear chamber. The front piston is deformed while being displaced through the constriction in the direction of the front end of the barrel while overcoming the resistance. The deformation establishes the liquid bypass connection. The rear chamber is filled with the liquid component. The rear chamber is sealed. A solution of the pharmaceutically active agent is charged in the front chamber. The front chamber is sealed.

A method for manufacturing an injectable preparation of a pharmaceutically active agent suitable for storage in a dual-chamber injection cartridge, said method comprising the steps of:

A. providing a dual chamber injection cartridge including a cartridge barrel having a front end and a rear end;
a front chamber in a vicinity of said front end of said barrel for a solid component of an injectable preparation;
a rear chamber in a vicinity of said rear end of said barrel for a liquid component of an injectable preparation;
a displaceable front piston of a resilient material for separating said front chamber and said rear chamber;
a closure for sealing said front end of said barrel;
a constriction arranged in said barrel between said front end and said rear end, said constriction having a non-circular cross-section;
and an openable bypass connection for permitting a passage of liquid from said rear chamber to said front chamber, wherein prior to opening said bypass connection said front piston is positioned between said constriction and said rear end of said barrel, said constriction exerting a resistance against a displacement of said front piston in a direction of said front end of said barrel when said piston is in a vicinity of said constriction, and such that said constriction prevents said front piston from being displaced toward said front end of said barrel when a vacuum exists in said front chamber and a pressure in a vicinity of atmospheric pressure exists in said rear chamber, and wherein said front piston is deformed while being displaced through said constriction in a direction of said front end of said barrel while overcoming said resistance, said deformation establishing said liquid bypass connection;
B. filling said rear chamber of said injection cartridge with said liquid component of the injectable preparation;
C. sealing said rear chamber;
D. charging a solution of the pharmaceutically active agent in said front chamber of said injection cartridge;
E. subjecting said injection cartridge to a freeze-drying process prior;
and
F. sealing said front chamber of said injection cartridge.

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Abstract

Claims24