United States Patent:  6,048,545

Assignee:  BioZone Laboratories, Inc. (Pittsburgh, CA)

Filed:  July 22, 1996

Substances, such as pharmaceuticals and cosmetics, are administered encapsulated within a lipid vesicle, by iontophoresis. An iontophoretic device which conforms to the contours of the body is also provided.

SUMMARY OF THE INVENTION

The present invention is directed to a method for administration to a subject of a substance encapsulated within a lipid vesicle, by iontophoresis. For example, the iontophoresis method of the invention can be used to facilitate transport of a substance in or through tissue/skin of a subject, that is in vivo (in or through the skin), ex vivo (in or through excised skin) and in vivo (in or through artificial skin).

The combination of liposomal delivery with iontophoresis is unexpectedly beneficial, because, it is non-invasive, the liposome encapsulation makes iontophoresis useful for non-polar substances and the iontophoresis improves the penetration and localization of liposome-encapsulated substance. The localization of the substance produce only a local effect, without any systemic activity, which is definitely desirable for dermal therapy.

The method of the invention can be used to obtain one or more of the following: to enhance penetration, to better control delivery, to provide a means of deeper delivery, to concentrate delivery, to localize delivery by decreasing systemic action, to target different layers of the skin for delivery, to increase the rate of delivery and the like. For example, experiments with crystal violet, basic and acid fuchsin colloidal iron, silver nitrate (used as markers) encapsulated in liposomes having positive, or negative surface charge demonstrate this. Conventional liposome anesthetic products are useful, but the lag time is usually 30 to 60 minutes. However, when charged liposome anesthetic products are used with iontophoresis, the lag time can be reduced to 5-10 minutes. The shorter lag time achieved by the iontophoresis makes the use of liposomal local anesthetics (for minor surgery or venepuncture) more practical.

By use of the method of the invention, particularly with a multiphase lipid vesicle compositions, substances can be incorporated into the subject in a concentration higher than their water or lipid solubility. Accordingly, the method using multiphase vesicle compositions is particularly useful for administering substances with low lipid or water solubility.

Claim 1 of 6 Claims

1. A method for administration of an substance selected from the group consisting of an uncharged dye and uncharged anesthetic to a subject comprising

applying directly to the skin or tissue of the subject a composition comprising said substance encapsulated within liposomes having either a positively or negatively charged surface by inotophoresis where the electric current is from about 1 to about 3 milliamperes and the duration is form about 1 to 15 minutes which causes dermal penetration.

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