Needleless drug injection device

A drug injector configured to inject a drug to a depth beneath an animal's skin comprising:

• a housing;
• a vial positioned within the housing, the vial holding a drug to be injected into a biological body;
• a nozzle associated with the housing through which the drug is injected;
• a piston positioned within the housing;
• and
• an actuator coupled to the piston, the actuator including a member of shape memory alloy, the actuator moving the piston towards the nozzle of the vial when a potential is applied to the member to expel the drug out of the vial through the nozzle, thereby delivering the drug to a depth beneath an animal's skin.

A drug injector configured to inject a drug to a depth beneath an animal's skin comprising:

• a housing;
• a vial positioned within the housing, the vial holding a drug to be injected into a biological body;
• a nozzle associated with the vial through which the drug is injected;
• a piston positioned within the housing;
• an actuator coupled to the piston, the actuator including a member of shape memory alloy, the actuator moving the piston towards the nozzle of the vial when a potential is applied to the member to expel the drug out of the vial through the nozzle;
• a skin sensor that measures skin properties of the body;
• and
• a servo-controller coupled to the actuator and the skin sensor, the servo-controller adjusting the injection pressure of the drug injector based on the skin properties.

A method of injecting a drug into a biological body comprising:

• holding a drug in a chamber, the chamber being in fluid communication with an nozzle through which the drug is injected;
• applying a potential to a member of an actuator, the member contracting upon the application of the potential, the actuator being coupled to a piston, the actuator moving the piston towards the nozzle when the potential is applied to the member;
• and
• expelling the drug from the chamber through the nozzle as the piston moves towards the chamber.

A method of injecting a drug into a biological body comprising:

• positioning a drug vial in a housing, the vial containing a drug to be injected into the body, and having an nozzle through which the drug is injected;
• applying a potential to a member of shape memory alloy, the member forming part of an actuator coupled to a piston positioned in the housing, the actuator moving the piston towards the nozzle when the potential is applied to the member;
• and
• expelling the drug from the vial through the nozzle as the piston moves towards the nozzle.