Claims for Patent: 5,344,656

Summary for Patent: 5,344,656

Title:	Subsaturated transdermal therapeutic system having improved release characteristics
Abstract:	Rate controlled transdermal delivery devices are disclosed which utilize an in-line adhesive to maintain the device on the skin and deliver an agent which is a solvent or a plasticizer for the in-line adhesive. The initial equilibrated concentration of the agent in the agent reservoir and the adhesive is below saturation, and the reservoir comprises the agent dissolved in a solvent with respect to which the rate controlling element of the device is substantially impermeable. In preferred embodiments the initial loading of the agent in reservoir is sufficient to prevent the activity of the agent in the reservoir from decreasing by more than about 50% and preferably no more than about 25% during the predetermined period of administration; and the thicknesses of the adhesive, rate controlling membrane and reservoir layers are selected so that at least 50% and preferably at least 75% initial equilibrated agent loading is in the reservoir layer. The devices are usable to deliver agents which are liquid at body temperatures such as benztropine, secoverine, nicotine, arecoline, polyethylene glycol monolaurate, glycerol monolaurate, glycerol monooleate and ethanol, for example.
Inventor(s):	Enscore; David J. (Sunnyvale, CA), Campbell; Patricia S. (Palo Alto, CA), Osborne; James L. (Mountain View, CA), Smart; Melinda K. (Sunnyvale, CA), Yum; Su I. (Los Altos, CA)
Assignee:	ALZA Corporation (Palo Alto, CA)
Application Number:	08/078,540
Patent Claims:	1. A transdermal active agent delivery device for delivering said agent over a predetermined administration period and utilizing an in-line adhesive comprising, in combination; a) an active agent capable of causing said adhesive to lose its adhesive properties; b) an agent reservoir containing said agent dissolved therein at: i) an initial equilibrated concentration such that the activity is less than 1.0 and at which said adhesive retains adhesive properties; and ii) at an initial loading sufficient to prevent the activity of said agent in said reservoir from decreasing by more than 50% during said administration period; and c) in-line adhesive means for maintaining said agent reservoir in agent transmitting relationship to the skin. 2. The device of claim 1 wherein activity of the agent in the reservoir does not exceed 0.25. 3. The device of claim 1 wherein the activity of the agent in the reservoir does not exceed 0.15. 4. A method for transdermally administering an active agent from a transdermal delivery device utilizing an in-line adhesive, said device comprising an active agent, capable of causing said adhesive to lose its adhesive properties, dissolved in a reservoir at a concentration less than saturation and in-line adhesive means for maintaining said reservoir in agent transmitting relationship to the skin, which method comprises: a) applying said device to the skin of a subject when the concentration of said agent in said reservoir is such that the activity is less than 1.0 and at a level at which the adhesive retains adhesive properties; and b) removing said device from the skin of said subject before the activity decreases by more than 50%. 5. The method of claim 4 wherein the activity when applied does not exceed 0.25. 6. The method of claim 4 wherein the activity when applied does not exceed 0.15. 7. In a transdermal delivery device utilizing an in-line adhesive for delivering an active agent during a predetermined administration period comprising an agent reservoir containing active agent capable of causing said adhesive to lose its adhesive properties dissolved therein at a concentration less than saturation with said in-line adhesive means disposed in the path of agent migration from said reservoir to the skin, the improvement wherein: a) the initial equilibrated concentration is such that the activity of said agent in said reservoir is less than 1.0 and is at a level at which the adhesive retains adhesive properties; and b) the initial loading of said agent in said reservoir is sufficient to prevent the activity of said agent from decreasing by more than 50% during said administration period. 8. The device of claim 7 wherein the activity of the agent in the reservoir does not exceed 0.25. 9. The device of claim 7 wherein the activity of the agent in the reservoir does not exceed 0.25. 10. The device of claim 1 wherein the activity of the agent in the reservoir does not exceed 0.50. 11. The method of claim 4 wherein the activity when applied does not exceed 0.50. 12. The device of claim 7 wherein the activity of the agent in the reservoir does not exceed 0.50.