Dermal delivery device with reduced loss of its volatile components

1. A transdermal drug delivery device that comprises:

a. an active ingredient (AI) layer, which is a polymer matrix having a skin contacting surface and a non-skin contacting surface and which comprises a volatile component;

b. a release liner adjacent the skin contacting surface of the AI layer, which release liner is impermeable to the volatile component and the perimeter of which extends beyond the perimeter of the AI layer in all directions; and

c. an overlay comprising a first pressure sensitive adhesive (PSA) adjacent the non-skin contacting surface of the AI layer, the perimeter of which extends beyond the perimeter of the AI layer in all directions,

wherein:

the AI layer is a polymer matrix comprising a second PSA, and the volatile component is at least partly solubilized in said second PSA;

the solubility of the volatile component in the first PSA of the overlay is less than the solubility of said component in the second PSA of the AI layer;

the release liner is in direct contact with the AI layer;

the release liner and the first PSA of the overlay are in contact with and adhered to each other around the perimeter of the AI layer to form a PSA seal that reduces or prevents loss of the volatile component from the AI layer;

the release liner is removable by peeling from the AI layer and the overlay PSA prior to applying to the skin; and the AI layer directly adheres to the skin and the first PSA of the overlay supplements the adhesion provided by the second PSA in the AI layer;

the volatile component comprises dimethyl sulfoxide (DMSO);

the first PSA is a polyisobutylene (PIB) PSA;

the second PSA is a polyacrylate PSA;

the overlay further comprises a polyacrylate PSA layer adjacent the non-skin contacting surface of the PIB PSA layer and a non-PSA overlay covering adjacent the non-PIB-PSA-layer-contacting surface of the polyacrylate PSA layer; and

adhesion of the layers is achieved without heat sealing.

2. The device of claim 1 in which

the release liner is a fluorinated or siliconized polyester film, or a foil lined with a siliconized or fluorinated polymer.

3. The device of claim 1 in which the non-PSA overlay covering is a polyurethane film, foam or spun bonded structure, a polyolefin foam, a PVC foam or a woven or non-woven fabric.

4. The device of claim 1 that further comprises an internal backing layer between the AI layer and the overlay.

5. The device of claim 1 in which the active ingredient is levonorgestrel or levonorgestrel in combination with ethinyl estradiol.