Transdermal systems for the delivery of ionic agents directly to open wounds and surgically repaired incisions

1. A transdermal system for the sustained delivery of an anesthetic agent directly to a selected site of an open skin wound by iontophoresis comprising:

a transdermal skin-worn patch that is configured to include when applied to an open skin wound:

(a) a donor chamber containing a donor electrode and a medium for containing an amount of anesthetic agent in a form suitable for transdermal delivery by iontophoresis in electrical communication with said donor electrode and a return electrode;

(b) a source configured to supply a low-level electric current in said patch that exhibits a low current density as applied to injured skin suitable for safe transdermal delivery of a desired dosage of said anesthetic agent through injured skin for a sustained duration, said source being connected in a circuit with said donor and return electrodes;

(c) wherein said donor electrode chamber further includes a provision for absorbing a quantity of fluid associated with weepage from adjacent injured skin tissue; and

(d) wherein said system is configured to deliver medication over a period of at least six hours.

2. A transdermal system as in claim 1 further comprising an amount of anesthetic agent in an epinephrine free formula in said patch.

3. A transdermal system as in claim 1 wherein said anesthetic agent is selected from lidocaine, bupivicaine, ropivicaine and mepivicaine in an epinephrine-free formula.

4. A transdermal system as in claim 2 wherein said anesthetic agent is selected from lidocaine, bupivicaine, ropivicaine and mepivicaine.

5. A transdermal system as in claim 1 wherein said current has a sustained delivery output ≦0.15 mA/cm 2 to the skin of a patient.

6. A transdermal system as in claim 1 comprising a current regulating device in said circuit for controlling the electrical output of said patch, and wherein delivery output current is maintained at <0.10 mA/cm 2 .

7. A transdermal system as in claim 4 wherein said anesthetic agent is lidocaine.

8. A transdermal system as in claim 1 wherein said donor electrode chamber is one of fixed volume that incorporates an absorbent pad for containing said anesthetic agent that has additional capacity to absorb a quantity of weepage fluid upon application to the skin.

9. A transdermal system as in claim 1 wherein said donor electrode chamber includes a pad for containing said anesthetic agent and includes an expansion chamber in communication therewith that includes an absorbent pad that provides additional capacity to absorb a quantity of weepage fluid upon application to the skin.

10. A transdermal system as in claim 1 comprising an expanding donor electrode chamber is provided with an absorbent pad for containing said anesthetic agent, said pad having additional capacity to absorb a quantity of weepage fluid while expanding the volume of said donor electrode chamber upon application to the skin.

11. A transdermal system as in claim 2 wherein said anesthetic agent is contained in a water-based solution.

12. A transdermal system as in claim 2 wherein said anesthetic agent is contained in the form of a gelled material.

13. A transdermal system as in claim 12 wherein said gel comprises hydroxypropylmethylcellulose (HPMC).

14. A transdermal system as in claim 1 wherein said provision for absorbing fluid includes an absorbent pad.

15. A transdermal system as in claim 14 wherein said absorbent pad comprises natural or synthetic fibrous material.

16. A method of administering an ionic therapeutic agent directly to a selected site of an open skin wound comprising:

(a) causing a skin-worn patch to be positioned over a selected skin site, wherein said patch comprises

(1) a donor chamber containing a donor electrode and an amount of therapeutic agent in a form suitable for transdermal delivery by iontophoresis in electrical communication with said donor electrode, said patch further comprising a return electrode;

(2) a source configured to supply a low-level electric current in said patch exhibiting a low current density as applied to injured skin suitable for safe transdermal delivery of a desired dosage of said therapeutic agent through injured skin for a sustained duration of at least 30 minutes, said source being connected in a circuit with said donor and return electrodes;

(3) wherein said donor electrode chamber further includes a provision for absorbing a quantity of fluid associated with weepage from adjacent injured skin tissue upon application to the skin;

(b) wherein the donor chamber of said patch is positioned over the desired treatment area; and

(c) maintaining said patch on said site for at least 30 minutes and up to 96 hours.