Iontophoresis drug delivery system

• US 4,931,046 A
• Filed: 02/22/1989
• Issued: 06/05/1990
• Est. Priority Date: 05/15/1987
• Status: Expired due to Term

• Current Assignee: Avitar, Inc.
• Original Assignee: Martin H. Newman
• Inventors: Newman, Martin H.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US07/314,297
• Time in Patent Office: 468 Days
• Field of Search: 604/20, 128/798, 128/802, 128/803, 128/419 R
• US Class Current: 604/20
• CPC Class Codes: A61M 2037/0007 having means for enhancing the permeation of substances through the epidermis, e.g. using suction or depression, electric or magnetic fields, sound waves or chemical agents
• CPC Class Codes: A61N 1/044 Shape of the electrode
• CPC Class Codes: A61N 1/0448 Drug reservoir
• CPC Class Codes: A61N 1/325 for iontophoresis, i.e. transfer of media in ionic state by an electromotoric force into the body electrodes for external use A61N1/0428

Abstract

A transdermal medication delivery system in which the medication is retained in a non-charged form such that it can be electrically charged. A d-c electrical current is supplied through the retained medication when it is in its electrically charged form and current control is used to control the current level. The electrical current supply circuit, the control circuit, the retained charged medication, and the body location of a patient to which the medication is to be delivered transdermally, form a closed loop during operation so that the current is maintained at a substantially constant level while being delivered to the body location. Such delivery can be terminated if the current exceeds a maximum allowable level.

Claims

1. A transdermal medication delivery system comprising

means for retaining a medication in a form such that it is capable of being electrically charged;

means for identifying the medication in said medication retaining means;

means for supplying a d-c electrical current through said medication retaining means at a selected body location of a patient to be treated when said medication is in its electrically charged form, said medication retaining means and said body location forming an electrical current path for causing said medication to be delivered from said medication retaining means to said body location transdermally when said electrical current is so supplied;

current control means for controlling the level of said electrical current in said current path;

said control means, said medication retaining means, said body location, and said electrical current supplying means forming a closed loop during operation whereby said current is supplied in a controlled manner such that said current is generally maintained at a substantially constant level while said medication is being transdermally delivered to said body location and whereby said delivery can be terminated if said current level exceeds a selected maximum allowable level; and

said control means further includes time control means responsive to said medication identifying means and to the substantially constant level of said electrical current for determining the treatment time over which said medication is to be delivered and for automatically terminating the delivery of said medication at the expiration of said treatment time.

2. A transdermal medication delivery system in accordance with claim 1 wherein said current supplying means comprises a programmable power source for supplying pulses of a controllable DC voltage having a selected polarity across a load which includes said medication retaining means and said body location so as to produce pulses of said current through said load.

3. A transdermal medication delivery system in accordance with claim 2 wherein said medication retaining means includes

an electrode for connection to said current supplying means;

means for retaining molecules of said medication capable of having a charge the polarity of which is opposite to the polarity of said controllable DC voltage.

4. A transdermal medication delivery system in accordance with claim 2 wherein said current supplying means supplies said current in the form of current pulses at a selected pulse repetition rate, or frequency, said current control means controlling the amplitude of said current pulses.

5. A transdermal medication delivery system in accordance with claim 4 wherein said selected pulse repetition rate, or frequency, is within a range from about 2 KHz to about 50 KHz.

6. A transdermal medication delivery system in accordance with claim 1 wherein said control means includes a microprocessor.

7. A transdermal medication delivery system in accordance with claim 1 wherein said medication identifying means includes indication bearing means associated with said medication retaining means for identifying said medication and further wherein said system includes

means for reading said indication bearing means to identify said medication and to supply said identification to said control means;

and

said time control means is responsive to the reading of said identification bearing means and to said substantially constant current level for determining the treatment time over which said medication is to be delivered to said body location and is further responsive to the expiration of said treatment time for terminating the delivery of said medication.

8. A transdermal medication delivery system in accordance with claim 7 wherein said indication bearing means is in the form of a bar code and said reading means is a bar code reader.

9. A transdermal medication delivery system in accordance with claim 1 and further including display means responsive to said control means for displaying selected information related to tho operation of said system.

10. A transdermal medication delivery system in accordance with claim 1 and further including alarm means responsive to said control means for indicating when delivery of said medication to said body location is completed.

11. A transdermal medication delivery system in accordance with claim 1 and further including sensing means for sensing one or more metabolic conditions of said patient, said control means responding to said one or more sensed conditions for further controlling the delivery of said medication to said body location.

12. A transdermal medication delivery system in accordance with claim 11 wherein said control means further controls the delivery of said medication by starting said delivery, by controlling the rate of said delivery, or by stopping said delivery in response to said sensing means.

13. A method of treating a selected body location by introducing a medication transdermally to said body location by applying an electrical current through said medication and said body location, said method comprises the steps of

identifying said medication;

determining a selected operating current level;

automatically determining the time of treatment based on the identifying of said medication and on the determining of said selected operating current level;

positioning electrically charged molecules of said medication adjacent to said body location;

applying said electrical current through said medication and said body location, the level of said current being applied in selected incremental steps until said selected operating current level is reached;

maintaining said current at said selected operating current level so as to introduce the charged molecules of said medication into said body location transdermally over said time of treatment; and

terminating said treatment when said time of treatment has elapsed.

14. A method in accordance with claim 13 and further including the step of terminating said treatment prior to said elapsed time if the operating current level exceeds a selected maximum allowable value.

15. A method in accordance with claim 14 wherein said selected maximum allowable current level is equal to twice said selected operating current level.

16. A method in accordance with claim 15 wherein said current applying step includes applying said current to said body location and said medication in incremental current amplitude steps until said selected operating current level is reached;

and

maintaining said selected operating current level substantially constant during said time of treatment.

17. A method in accordance with claim 13 wherein said selected operating current level determining step includes the steps of

applying said electrical current to said body location without the presence of said medication in incremental current amplitude steps until a first level of current amplitude is reached at which a patient whose body location is to be medicated feels a perceived sensation;

and

reducing said current level by a predetermined amount, said operating current level being selected at said reduced current level.

18. A method in accordance with claim 13 wherein said medication positioning step includes

selecting a medication package containing non-electrically charged molecules of a medication in a matrix of a hydrophilic membrane;

exposing a portion of said membrane;

moistening the exposed portion of said membrane with water to cause the molecules of medication therein to become electrically charged; and

positioning the exposed surface of said membrane with said electrically charged molecules of medication therein adjacent to said body location.