Iontophoretic delivery device and power supply therefor

• US 5,374,242 A
• Filed: 12/07/1993
• Issued: 12/20/1994
• Est. Priority Date: 12/03/1991
• Status: Expired due to Term

• Current Assignee: ALZA Corporation (Johnson & Johnson)
• Original Assignee: ALZA Corporation (Johnson & Johnson)
• Inventors: Mc Nichols, Larry A., Badzinski, John D., Haak, Ronald P.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Casler, Brian L.
• Application Number:
  US08/164,663
• Time in Patent Office: 378 Days
• Field of Search: 607/75, 607/115, 607/152, 607/153, 604/20, 604/21
• US Class Current: 604/20
• CPC Class Codes: A61N 1/30 Apparatus for iontophoresis, i.e. transfer of media in ionic state by an electromotoric force into the body, or cataphoresis

Abstract

An iontophoretic drug-delivery device incorporating a power supply which minimizes the cost of the batteries needed by operating the batteries in a series configuration at the start of delivery, when the patient'"'"'s skin resistance is high, and by switching the batteries into a parallel configuration when skin resistance drops. An automatic switching circuit for achieving this transition is included.

Claims

1. An iontophoretic delivery system for delivering a beneficial agent by iontophoresis through an intact body surface of a patient having an associated body surface electrical resistance, the system comprising:

a first electrode means for containing a beneficial agent to be delivered and for contacting a body surface of a patient in agent-transmitting relation therewith;

a second electrode means for contacting the body surface in ion-transmitting relation therewith at a location spaced apart from the first electrode means;

first and second electrical power sources, each having a pair of terminals and each producing an electrical potential difference between its said pair of terminals; and

bi-state switch means, coupled to said two power sources and said first and second electrode means, for selectively switching between;

(1) a first state, in which said two power sources are connected in series circuit relation between said first and second electrode means, and (2) a second state, in which said two power sources are connected in parallel circuit relation between said first and second electrode means, where switching occurs in response to a change of electrical resistance of the patient'"'"'s body surface.

2. The iontophoretic delivery system of claim 1 wherein said bi-state switch means comprises a manually operable switch.

3. The iontophoretic delivery system of claim 1 wherein at least one of said power sources comprises a DC source.

4. The iontophoretic delivery system of claim 1 wherein at least one of said power sources comprises a lithium battery.

5. The iontophoretic delivery system of claim 1 comprising a unitary iontophoretic delivery device incorporating said first and second electrode means.

6. The iontophoretic delivery system of claim 5 wherein said unitary iontophoretic delivery device further incorporates said two electrical power sources and said bi-state switch means.

7. The iontophoretic delivery system of claim 1, further including switch control means, coupled to said bi-state switch means and at least one of said first and second electrode means, for:

(1) sensing the value of an electrical parameter present at least one of said first and second electrode means and associated with the delivery of electrical power from said power sources to said first and second electrode means, and (2) comparing the value of said sensed parameter with a pre-established value thereof, and (3) causing said bi-state switch means to transit between said first and second states, according to where the sensed parameter value lies in relation to the pre-established value.

8. The iontophoretic delivery system of claim 7 wherein said bi-state switch means comprises at least one field-effect transistor (FET).

9. The iontophoretic delivery system of claim 7, wherein said sensed parameter value is a voltage related to the resistance between said first and second electrode means.

10. The iontophoretic delivery system of claim 7, wherein said switch control means comprises a switching transistor coupled to at least one of said first and second electrode means and responding to the voltage thereat by causing said bi-state switch means to transit from said first state to said second state when said voltage exceeds said pre-established value.

11. The iontophoretic delivery system of claim 1, further including a constant current regulator coupled to said power sources and said first and second electrode means.

12. The iontophoretic delivery system of claim 11 wherein said constant current regulator comprises a JFET transistor.

13. The iontophoretic delivery system of claim 1, wherein said bi-state switch means comprises:

a first electrical switch connected to a lower voltage terminal of said first power source and said first electrode means;

a second electrical switch connected to the lower voltage terminal of said first power source and a higher voltage terminal of said second power source;

a third electrical switch connected to said second electrode means and a higher voltage terminal of said second power source;

where a higher voltage terminal of said first power source is connected to said second electrode means and a lower voltage terminal of said second power source is connected to said first electrode means; and

where the first electrical switch and the third electrical switch are both open.

14. The iontophoretic delivery system of claim 1, wherein said bi-state switch means comprises:

a first electrical switch connected to a lower voltage terminal of said first power source and said first electrode means;

a second electrical switch connected to the lower voltage terminal of said first power source and a higher voltage terminal of said second power source;

a third electrical switch connected to said second electrode means and a higher voltage terminal of said second power source;

where a higher voltage terminal of said first power source is connected to said second electrode means and a lower voltage terminal of said second power source is connected to said first electrode means; and

where the first electrical switch and the third electrical switch are both closed.

16. The iontophoretic delivery system of claim 1 or 15, wherein the bi-state switch means comprises an automatically operable switch.

17. The iontophoretic delivery system of claim 1 or 15, wherein switching occurs when the body surface electrical resistance drops to a level below about 30 kohm-cm².

18. The iontophoretic delivery system of claim 1 or 15, wherein switching occurs when the body surface electrical resistance drops to a level of about 20 to 30 kohm-cm².

27. The method of claim 18, further comprising the steps of:

sensing an electrical parameter associated with the delivery of electrical power from said power sources to said first and second electrode means;

comparing the sensed value of the electrical parameter with a pre-established value thereof; and

switching said power sources from said first state to said second state if said electrical parameter has a value above said pre-established value.

28. The method of claim 27, wherein said sensing step comprises sensing of the voltage at one of said first and second electrode means.

15. An iontophoretic delivery system for delivering a beneficial agent by iontophoresis through an intact body surface of a patient, said body surface having an electrical resistance, the system comprising:

a first electrode means for containing a beneficial agent to be delivered and for contacting the body surface of the patient in agent-transmitting relation therewith;

a second electrode means for contacting the body surface in ion-transmitting relation therewith at a location spaced apart from the first electrode means;

at least two electrical power sources, each producing an electrical potential difference; and

bi-state switch means, coupled to said power sources and said first and second electrode means, for selectively switching between;

(1) a first state, in which said two power sources are connected in series circuit relation between said first and second electrode means, and (2) a second state, in which said two power sources are connected in parallel circuit relation between said first and second electrode means, where switching occurs after the electrical resistance of the body surface drops from an initial electrical resistance level to a level substantially below said initial level.

19. The iontophoretic delivery system of claim 15, further including switch control means, coupled to said bi-state switch means and at least one of said first and second electrode means, for (1) sensing a value of an electrical parameter present at at least one of said first and second electrode means and associated with the delivery of electrical power from said power sources to said first and second electrode means, and (2) comparing the value of said sensed parameter with a pre-established value thereof, and (3) causing said bi-state switch means to transit between said first and second states, according to where the sensed parameter value lies in relation to the pre-established value.

20. The iontophoretic delivery system of claim 15, wherein said bi-state switch means comprises at least one field effect transistor.

21. An iontophoretic delivery system for delivering a beneficial agent by iontophoresis through an intact body surface of a patient having an associated body surface electrical resistance, the system comprising:

a first electrode means for containing a beneficial agent to be delivered and for contacting a body surface of a patient in agent-transmitting relation therewith;

a second electrode means for contacting the body surface in ion-transmitting relation therewith at a location spaced apart from the first electrode means;

at least two electrical power sources, each having a pair of terminals and each producing an electrical potential difference between its said pair of terminals;

bi-state switch means, coupled to said two power sources and said first and second electrode means, for selectively switching between;

(1) a first state in which said two power sources are connected in series circuit relation between said first and second electrode means, and (2) a second state in which said two power sources are connected in parallel circuit relation between said first and second electrode means; and

switch control means, coupled to said bi-state switch means and at least one of said first and second electrode means, for sensing the voltage at one of said first and second electrode means and for causing said bi-state switch means to transit between its first state and its second state, according to where the sensed voltage lies in relation to a pre-established voltage value.

22. The iontophoretic delivery system of claim 21 wherein said bi-state switch means comprises a plurality of field-effect transistors (FETs).

23. The iontophoretic delivery system of claim 21, wherein said switch controls means comprises a switching transistor coupled to at least one of said first and second electrode means and responding to said sensed voltage thereat by causing said bi-state switch means to transit from said first state to said second state in response to said sensed voltage exceeding said pre-established voltage value.

24. The iontophoretic delivery system of claim 21, further including a constant current regulator coupled to said power sources and said first and second electrode means.

25. The iontophoretic delivery system of claim 24 wherein said constant current regulator comprises a JFET transistor.

26. A method of delivering a beneficial agent from an iontophoretic delivery system through a body surface of a patient, said body surface having an electrical resistance, the method comprising:

providing at least two electrical power sources to drive the delivery system;

electrically connecting the two power sources to first and second electrode means, the first electrode means containing a beneficial agent to be delivered, the first and second electrode means being for making electrical contact between the delivery system and the patient;

placing the first electrode means in agent-transmitting relation with the body surface;

placing the second electrode means in ion-transmitting relation with the body surface at a location spaced apart from the first is electrode means; and

switching the two electrical power sources between (1) a first state in which the two power sources are connected in series circuit relation to the first and second electrode means when the body surface exhibits a high electrical resistance, and (2) a second state in which the two power sources are connected in parallel circuit relation to the first and second electrode means when the body surface exhibits an electrical resistance that is lower than the high resistance associated with the first state.

29. The method of claim 26, wherein the switching of the power sources occurs automatically.

30. The method of claim 26, wherein switching occurs when the body surface electrical resistance drops to a level below about 30 kohm-cm².

31. The method of claim 26, wherein switching occurs when the body surface electrical resistance drops to a level of about 20 to 30 kohm-cm².

32. The method of claim 26, further comprising:

sensing an electrical parameter associated with the delivery of electrical power from said power sources to said first and second electrode means;

comparing the sensed value of the electrical parameter with a pre-established value thereof; and

causing said power sources to transit between said first and second states according to where the sensed parameter value lies in relation to said pre-established value.

33. The method of claim 26, wherein the switching between the first and second states occurs with the two power sources connected between the first and second electrode means.