Methods and apparatus for buffering parenteral solutions

A device for transferring a volume of a solution from a first cartridge having a septum to another solution in a second cartridge having a septum, said device comprising:

• a cartridge holder having a proximal end, a distal end, and a chamber for removably holding the first cartridge;
• a plunger driver attachable to the proximal end of the cartridge holder and having a piston rod which engages a plunger on the first cartridge;
• and
• a cartridge connector having a proximal end attachable to the distal end of the cartridge holder, a distal end adapted to engage a septum end of the second cartridge, and a sealed interior waste chamber, said cartridge connector including a transfer needle and an exhaust needle which extend distally to penetrate the septum end of the second cartridge, wherein the transfer needle extends proximally to penetrate the septum of the first cartridge and the exhaust needle terminates in the sealed interior waste chamber.

A cartridge connector for providing fluid transfer paths between a first cartridge having a septum and a second cartridge having a septum, said cartridge connector comprising:

• a body having a first end, a second end and a sealed interior waste chamber;
• a transfer needle having a first end exposed at the first end of the body and a second end exposed at the second end of the body, wherein both the first and second ends of the transfer needle are capable of penetrating a cartridge septum;
• and
• an exhaust needle having a first end exposed at the first end of the body and a second end terminating in the sealed interior waste chamber, wherein the first end of the exhaust needle is capable of penetrating a cartridge septum.