Title:  Stereospecific delivery of a drug using electrotransport

United States Patent:  6,136,327

Assignee:  ALZA Corporation (Mountain View, CA)

Filed:  December 1, 1997

Preferential delivery via electrotransport of a preferred isomeric form of a pharmaceutically active chiral compound from a mixture of the isomeric forms of said compound is provided. A method of decreasing the delivery via electrotransport of a less preferred isomer of a drug is also provided. Drug delivery devices suitable for such preferential delivery and methods of making the same are also provided.

SUMMARY OF THE INVENTION

The invention thus provides a method for using electrotransport drug delivery to preferentially deliver a preferred isomer from a pharmaceutical formulation containing the drug as a mixture of preferred and less preferred isomers. The method involves (a) applying to an area of the body surface a formulation containing the drug as a mixture of isomers, and (b) delivering the formulation by electrotransport through the same area of the body surface simultaneously with or subsequent to step (a), so that the transport of a preferred isomer is enhanced relative to the transport of a less preferred isomer. Generally, the method will involve: placing an electrotransport drug reservoir in drug-transmitting relation to the selected area of the body surface, the reservoir containing the aforementioned formulation; electrically connecting the drug reservoir to a source of electrical power; and then delivering the drug through the body surface by electrotransport. As explained above, the process is carried out such that the preferred enantiomer is delivered at a rate sufficient to induce a therapeutic effect, while the corresponding, second enantiomer is delivered at a substantially lower rate. A method of decreasing the delivery via electrotransport of a less preferred isomer of a drug is also provided. Drug delivery devices suitable for such preferential delivery and methods of making the same are also provided.

Claim 1 of 22 Claims

What is claimed is:

1. A method for preferentially delivering through a body surface a preferred isomer of a drug from a formulation containing the drug as a racemic mixture of said preferred isomer and a less preferred isomer, comprising;

(a) applying to an area of the body surface the formulation containing the drug as a racemic mixture of isomers; and

(b) delivering the drug by electrotransport through said area simultaneously with or subsequent to step (a), in a manner effective to enhance the transport of said preferred isomer from the racemic mixture relative to the transport of said less preferred isomer from the racemic mixture.

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