United States Patent:  5,985,316

Assignee:  Alza Corporation (Palo Alto, CA)

Filed:  April 28, 1995

An electrotransport device (10) for transdermal delivery of an agent through a body surface has a donor reservoir (16) which contains a compound formed of the agent and a transdermal permeation enhancer, the compound being able to dissociate into an agent ion and an enhancer counter ion. Methods of enhancing transdermal electrotransport drug delivery and methods of forming a composition exhibiting enhanced transdermal electrotransport drug delivery are also provided.

DISCLOSURE OF THE INVENTION

The present invention provides a method of adding a permeation enhancer to the donor reservoir of an electrotransport delivery device which substantially avoids the introduction of competing ions thereto. An electrotransport donor reservoir composition, including both a therapeutic agent and a permeation enhancer but substantially free of competing permeation enhancer ions, is also provided. The invention involves a composition comprising the therapeutic agent to be delivered, wherein the agent is in the form of an agent-enhancer compound. The agent-enhancer compound may be formed by reacting the agent, in the form of a base, with an acid permeation enhancer, such as a fatty acid. Alternatively, the agent-enhancer compound may be formed by reacting the agent in the form of an acid, with a base permeation enhancer, such as a pyrrolidone. The agent-enhancer compound is preferably a water soluble salt. When the agent enhancer compound is dissolved in a liquid (eg, aqueous) solvent, a solution comprised of therapeutic agent ions and oppositely charged permeation enhancer counterions is formed. The solution is substantially free of competing permeation enhancer ions having the same charge as the therapeutic agent ions. The invention also contemplates an electrotransport delivery device comprising donor and counter electrodes wherein the donor electrode contains the composition of this invention.

Claim 1 of 25 Claims

1. A donor reservoir for an electrotransport therapeutic agent delivery device, the reservoir containing a composition comprising a therapeutic agent-permeation enhancer compound and a liquid solvent for the therapeutic agent-permeation enhancer compound wherein therapeutic agent ions and permeation enhancer ions of opposite charge are formed in the donor reservoir when the therapeutic agent-permeation enhancer compound dissolves in the liquid solvent, the permeation enhancer ions being effective to enhance electrotransport flux of the therapeutic agent ions through a body surface.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.