Injection methods using a servo-controlled needle-free injector

Abstract

A method for injecting a substance through a biological body surface includes providing a needle-free transdermal transport device configured to inject the substance through the surface. The substance is injected into the biological body with the transport device while a parameter of the injection is sensed and a servo-controller is used to dynamically adjust at least one injection characteristic based on the sensed parameter. The substance is injected for (i) a first time period during which a first portion of a volume of the substance is injected at a first injection pressure, and (ii) a second time period during which a remainder of the volume of the substance is injected at a second injection pressure. A viscosity of the substance may be determined, and a pressure calculated for injecting the substance based on the viscosity. The substance may be injected with the transport device by using the calculated pressure.

What is claimed is: 
     
         1 . A method for injecting a substance through a surface of a biological body, the method comprising the steps of:
 providing a needle-free transdermal transport device configured to inject the substance through the surface of the biological body; and   injecting the substance with the needle-free transdermal transport device, the injection being controlled in response to an indication of a viscosity of the substance.   
     
     
         2 . The method of  claim 1 , further comprising sensing the indication of the viscosity of the substance. 
     
     
         3 . The method of  claim 2 , wherein sensing the indication of the viscosity of the substance comprises using the needle-free transdermal transport device to fill an ampoule with the substance, the sensed indication of the viscosity being a force used to fill the ampoule. 
     
     
         4 . The method of  claim 2 , wherein sensing the indication of the viscosity of the substance comprises sensing pressure when filling an ampoule with the substance. 
     
     
         5 . The method of  claim 2 , wherein sensing the indication of the viscosity of the substance comprises sensing velocity when filling an ampoule with the substance. 
     
     
         6 . The method of  claim 2 , wherein the needle-free transdermal transport device comprises a servo-controller, the servo-controller controlling the injection based on the sensed indication of the viscosity. 
     
     
         7 . The method of  claim 6 , wherein the needle-free transdermal transport device further comprises a linear Lorentz-force actuator coupled to the servo-controller, the actuator causing injection of the substance in response to an input received from the servo-controller. 
     
     
         8 . The method of  claim 2 , wherein the sensed indication of the viscosity of the substance is temperature. 
     
     
         9 . The method of  claim 1 , further comprising pre-programming the needle-free transdermal transport device with the indication of the viscosity of the substance. 
     
     
         10 . The method of  claim 1 , wherein the substance comprises a polymeric material having at least one property that is temperature-dependent. 
     
     
         11 . The method of  claim 10 , wherein the substance comprises a biodegradable polymer allowing controlled release of a drug contained therein. 
     
     
         12 . A method for injecting a substance through a surface of a biological body, the method comprising the steps of:
 providing a needle-free transdermal transport device configured to inject the substance through the surface of the biological body;   determining a viscosity of the substance;   calculating a pressure for injecting the substance based on the determined viscosity; and   injecting the substance with the needle-free transdermal transport device by using the calculated pressure.   
     
     
         13 . The method of  claim 12 , wherein the substance comprises a viscous solution. 
     
     
         14 . The method of  claim 12 , wherein the substance comprises a polymeric material having at least one property that is temperature-dependent. 
     
     
         15 . The method of  claim 14 , wherein the substance comprises a biodegradable polymer allowing controlled release of a drug contained therein. 
     
     
         16 . The method of  claim 12 , wherein determining the viscosity of the substance comprises pre-programming the needle-free transdermal transport device with the viscosity. 
     
     
         17 . The method of  claim 12 , wherein determining the viscosity of the substance comprises using the needle-free transdermal transport device to fill an ampoule with the substance, and calculating the viscosity on the basis of a force used to fill the ampoule. 
     
     
         18 . The method of  claim 12 , wherein determining the viscosity of the substance comprises sensing during the injection of the substance a change in at least one of pressure and velocity required for injection of the substance. 
     
     
         19 . The method of  claim 18 , wherein the needle-free transdermal transport device comprises a servo-controller, and the servo-controller calculates the injection pressure based on the determined viscosity.