External drug pump
Apparatus is described for administering a substance to a subject. A vial contains the substance and a stopper is disposed within the vial and is slidably coupled to the vial. A first threaded element is (a) rotatable with respect to the vial and (b) substantially immobile proximally with respect to the vial during rotation of the first threaded element. A second threaded element is threadedly coupled to the first threaded element. At least a distal end of the second threaded element is substantially non-rotatable with respect to the vial, and the distal end of the second threaded element defines a coupling portion that couples the second threaded element to the stopper. The first threaded element, by rotating, linearly advances the stopper and at least the distal end of the second threaded element toward a distal end of the vial. Other embodiments are also described.
1. An apparatus for administering a substance to a subject, the apparatus comprising:
a container configured to contain the substance, the container extending along a longitudinal axis;
a stopper slidably received within the container and configured to seal the container;
a first threaded element configured to rotate relative to the container and is substantially immobile proximally with respect to the container during rotation of the first threaded element;
a second threaded element coupled to the first threaded element, a distal end of the second threaded element being coupled to the stopper, wherein rotation of the first threaded element is configured to linearly advance the second threaded element and the stopper distally through the container, and wherein the second threaded element is substantially rotationally fixed relative to the container throughout advancement of the stopper through the container;
a motor configured to drive rotation of the first threaded element; and
a battery configured to power the motor.
2. The apparatus of claim 1 , further comprising a plurality of cog wheels configured to transfer force from the motor to the first threaded element.
3. The apparatus of claim 2 , wherein the plurality of cog wheels comprises a first cog wheel coupled to the first threaded element and a second cog wheel coupled to the motor, the first and second cog wheels spaced apart along a direction perpendicular to the longitudinal axis.
4. The apparatus of claim 3 , wherein the first and second cog wheels are configured to rotate about parallel axes that are parallel to the longitudinal axis.
5. The apparatus of claim 4 , wherein the motor is spaced from the container.
6. The apparatus of claim 5 , wherein the motor extends along an axis that is parallel to the longitudinal axis of the container.
7. The apparatus of claim 3 , further comprising a housing, wherein the first cog wheel has a proximal projection received within a portion of the housing to impede linear motion of the first threaded element.
8. The apparatus of claim 1 , wherein one of the first and second threaded elements is partially disposed concentrically within the other of the first and second threaded elements.
9. The apparatus of claim 1 , wherein the second threaded element is a nut.
10. The apparatus of claim 1 , further comprising a container piercing mechanism configured to pierce a seal at a distal end of the container.
11. The apparatus of claim 1 , further comprising a tube in fluid communication with the container.
12. The apparatus of claim 1 , further comprising a control unit configured to control the motor.
13. The apparatus of claim 12 , further comprising a push button configured to provide an input to the control unit.
14. The apparatus of claim 1 , wherein the second threaded element has a shape configured to prevent rotation of the second threaded element relative to the container.
15. The apparatus of claim 14 , wherein the second threaded element has grooves configured to engage and slide along protrusions during advancement to prevent rotation of the second threaded element relative to the container.
16. An apparatus for administering a substance to a subject, comprising:
a housing;
a container configured to contain the substance, the container extending along a longitudinal axis;
a stopper slidably received within the container and configured to seal the container;
a first threaded element configured to rotate relative to the container, the first threaded element having a first cog wheel having a proximal projection received within a portion of the housing to impede linear motion of the first threaded element relative to the housing and the container;
a second threaded element coupled to the first threaded element, a distal end of the second threaded element being coupled to the stopper, wherein rotation of the first threaded element is configured to linearly advance the second threaded element and the stopper distally through the container, and wherein the second threaded element has a shape configured to substantially prevent rotation of the second threaded element relative to the container throughout advancement of the stopper through the container;
a motor;
a second cog wheel coupled to the motor, wherein the first cog wheel and the second cog wheel are configured to rotate about parallel axes and configured to transfer force from the motor to rotate the first threaded element; and
a battery configured to power the motor.
17. The apparatus of claim 16 , wherein one of the first and second threaded elements is partially disposed concentrically within the other of the first and second threaded elements.