Needleless jet injector system with separate drug reservoir

A needleless jet injection assembly for injecting a fluid medicament through the skin of the patient which comprises:

• a body member formed with a fluid pathway, said fluid pathway having a first opening and a second opening;
• a reservoir attached to said body member at said first opening of said fluid pathway;
• means formed on said body member at said first opening of said fluid pathway and engageable with said reservoir for establishing fluid communication between said reservoir and said fluid pathway;
• an impulse chamber formed on said body member, said impulse chamber being connected in fluid communication with said second opening of said fluid pathway for receiving said fluid medicament from said reservoir;
• a nozzle formed with a tip extending from said body member to establish fluid communication between said impulse chamber and said tip;
• a plunger slidably mounted on said body member for advancement into said impulse chamber;
• and
• an impulse generator having a ram for striking said plunger to create a force for injecting said fluid medicament from said impulse chamber, through said tip and into the patient.

A method for injecting a fluid medicament through the skin of a patient comprising the steps of:

• providing a device formed with a spike and a fluid pathway, said fluid pathway having a first opening and a second opening, and said spike being connected in fluid communication with said first opening of said fluid pathway, and further wherein said device has an impulse chamber formed with a tip, said impulse chamber being connected in fluid communication with said second opening of said fluid pathway to establish fluid communication from said spike through said fluid pathway and through said tip;
• selectively engaging a cartridge with said device, wherein said spike pierces said cartridge to establish fluid communication from said cartridge through said fluid pathway and into said impulse chamber;
• positioning said tip of said device against the skin of the patient;
• and
• creating a force for injecting said fluid medicament from said impulse chamber through said tip and through the skin of the patient.