Iontophoretic controller

• US 6,047,208 A
• Filed: 08/27/1997
• Issued: 04/04/2000
• Est. Priority Date: 08/27/1997
• Status: Expired due to Fees

• Current Assignee: Vyteris, Inc.
• Original Assignee: Becton, Dickinson & Co
• Inventors: Flower, Ronald J.
• Primary Examiner(s): MCDERMOTT, CORRINE MARIE
• Application Number:
  US08/924,764
• Time in Patent Office: 951 Days
• Field of Search: 604/20, 604/65, 604/67, 607/152, 607/1-3, 607/59, 607/62
• 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 controller is provided. The controller is electrically connected via two electrical connectors to a patch consisting of two electrodes, the two electrodes are respectively positioned in an active reservoir and a return reservoir of the patch. A current is applied to the patch when the iontophoretic controller is turned on or otherwise activated. A waveform, such as the patch voltage, is measured over a predetermined time interval. A change in the measured voltage is compared to a threshold. If the change in measured voltage exceeds the threshold, the controller takes an action, such as providing a warning or discontinuing the application of current.

Claims

1. An iontophoretic controller, connectable to a patch having a plurality of electrodes via a respective plurality of electrical connectors, at least two of said plurality of electrodes respectively positioned in an active reservoir and a return reservoir of the patch, said controller comprising:

a power source having a plurality of connectors attachable to a plurality of electrodes on the patch when the patch is disposed on a patient for supplying power to the patch so that the patch provides a measurable waveform to the controller through said connectors in response to an impedance of the patient;

means for measuring a voltage waveform and a current waveform of the patch, and Generating an impedance waveform therefrom over a predetermined time interval; and

means for comparing said impedance waveform to a predetermined impedance waveform, wherein said controller takes an action when said comparing means detects a difference between the generated waveform and the predetermined waveform.

2. An iontophoretic controller according to claim 1, wherein said power source comprises one of a group of a current source, a voltage source and a Thevenin equivalent source.

3. An iontophoretic controller, connectable to a patch having a plurality of electrodes via a respective plurality of electrical connectors, at least two of said plurality of electrodes respectively positioned in an active reservoir and a return reservoir of the patch, said controller comprising:

means, having a plurality of connectors, for supplying a current through the patch through the plurality of connectors to the plurality of electrodes when said controller is activated and said controller is connected to the patch;

means for measuring a change in a voltage, related to said supplied current, across the patch over a predetermined time interval; and

means for comparing the measured change in voltage to a threshold, wherein said controller takes an action when said comparing means determines that the change in measured voltage exceeds the threshold determined from prior voltage measurements.

4. An iontophoretic controller according to claim 3 wherein the threshold is a predetermined positive number.

5. An iontophoretic controller according to claim 3, wherein the action taken is a warning action.

6. An iontophoretic controller according to claim 5, wherein the warning action comprises causing an audio alarm.

7. An iontophoretic controller according to claim 5, wherein the warning action comprises causing a visual alarm.

8. An iontophoretic controller according to claim 5, wherein the warning action comprises causing a tactile alarm.

9. An iontophoretic controller according to claim 3 wherein the action taken includes discontinuing the supply of the current by said current supplying means.

10. An iontophoretic controller according to claim 3, further comprising means for switching between the patch and an auxiliary patch, and the action taken is a switching between the patch and the auxiliary patch.

11. An iontophoretic controller according to claim 3, wherein the comparison is performed by said comparing means after the supply of current has reached a steady state.

12. An iontophoretic controller according to claim 3, wherein the change in voltage is determined from a presently measured voltage and a previously measured voltage.

13. An iontophoretic controller according to claim 12, wherein the previously measured voltage is a minimum previously measured voltage.

14. An iontophoretic controller according to claim 3, wherein said current supplying means comprises a current source, said voltage measuring means comprises a differential amplifier to measure the voltage across the patch and an analog to digital converter to convert the measured to a digital voltage, and said comparing means comprises a microprocessor to compare the digital voltage values.

15. An iontophoretic controller connectable to a patch having a plurality of electrodes via a respective plurality of electrical connectors, at least two of said plurality of electrodes respectively positioned in an active reservoir and a return reservoir of the patch, said controller comprising:

means, including a power source having a plurality of connectors, comprising a battery serially connected to a switch connected by the plurality of connectors to the plurality of electrodes, for controlling a voltage across the patch when said controller is activated and said controller is connected to the patch;

means for measuring a chance in a current, comprising a resistor, a differential amplifier for measuring the voltage across said resistor so as to measure the current, and an analog to digital converter for converting the measured current to a digital current value, related to said voltage across said patch, supplied through the patch over a predetermined time interval; and

means for comparing the measured change in current to a threshold, comprising a microprocessor which compares the digital current values, wherein said controller takes an action when said comparing means determines that the change in measured current exceeds the threshold.

16. An iontophoretic controller according to claim 15, wherein the action taken includes stopping the application of voltage by opening said switch.

17. An iontophoretic controller, connectable to a patch having a plurality of electrodes via a respective plurality of electrical connectors, at least two of said plurality of electrodes respectively positioned in an active reservoir and a return reservoir of the patch, said controller comprising:

means for supplying a current comprising a current source and a plurality of connectors, through the plurality of connectors to the plurality of electrodes through the patch when said controller is activated and said controller is connected to the patch;

means for measuring a change in a voltage related to said supplied current, comprising a differential amplifier to measure the voltage across the patch over a predetermined time interval and an analog to digital converter to convert the measured voltage to a digital voltage value;

means for measuring a change in said current supplied through the patch comprising a resistor, a different amplifier for measuring the voltage across said resistor so as to measure the current over said predetermined time interval, and the analog to digital converter for converting the measured current to a digital current value;

means for computing a change in load impedance from the measured change in voltage and current over the predetermined time interval; and

means for comparing the measured change in impedance to a preselected threshold, comprising a microprocessor which computes the load impedances from the digital voltage and current values and compares the computed load impedances, wherein said controller takes an action when said comparing means determines that the change in computed load impedance exceeds the threshold.

18. A method for controlling an iontophoretic controller, operatively connected to a patch including at least two electrodes via a respective at least two electrical connectors, the at least two electrodes respectively positioned in an active reservoir and a return reservoir of the patch, said method comprising the steps of:

supplying a current through the patch when the controller is activated;

measuring a change in a voltage across the patch over a predetermined time interval;

measuring a change in current supplied through the patch over the predetermined time interval;

computing a change in load impedance from the measured change in voltage and current over the predetermined time interval; and

comparing the measured change in impedance to a threshold, wherein the controller takes an action when the change in computed load impedance exceeds the threshold.