US 5,667,798 A · Transdermal drug delivery system

Abstract

In a transdermal drug delivery system, encapsulation material used to coat drug granules controls the release of an active ingredient. The active ingredient is released into a water retaining matrix, which acts as a reservoir, and transdermal drug penetration is driven by the resulting concentration gradient. The delivery system is enclosed in a patch comprising a composite shell, which acts as an occlusive covering when attached to skin, thus enhancing the hydration of the skin area and fostering absorption of the drug. Visible change indicators incorporated into the system provide indicators at significant "landmarks" in the lifetime of the patch. Microcapsules used for the indicator may be formulated so that the penetration of moisture effects a color change at a time when the active ingredient is almost exhausted. This feature alerts to the user to the need for application of a replacement patch.

Claims16

Dependent claims

A drug delivery system for the release and delivery of a drug across the skin of a user comprising:

a shell, said shell providing an occlusive covering on the skin of the user to enhance the hydration of the skin, said shell comprising a reservoir having a first face and a second face, said reservoir having therein a matrix adapted to absorb moisture from the skin and hydrate the skin to facilitate penetration of the skin by a drug, said reservoir further having therein a plurality of microcapsules, said microcapsules being dispersed within said matrix and having contained therein an effective concentration of a drug and a coating formulated to be susceptible to penetration by moisture;
means on said first face of said reservoir for adhering said shell to the skin;
and
a visible indicator operatively associated with said second face of said reservoir, said indicator comprising a reagent formulated to visibly change in response to the presence of moisture, electrolytes or other secretions in said matrix, wherein said release of said drug and said visible indicator are activated by a common mechanism.

1 more element

Dependencies are inferred from the claim text.

Transdermal drug delivery system

Life of this patent

Transdermal drug delivery system

Life of this patent

Abstract

Claims16