Claims for Patent: 5,164,190

Summary for Patent: 5,164,190

Title:	Subsaturated transdermal drug delivery device exhibiting enhanced drug flux
Abstract:	Transdermal administration of hydrophobic drugs via a diffusion mechanism in which the drug is dissolved in a carrier at concentrations that are 20% to 80% of the saturation concentration. The flux of drug from the device is non-Fickian and is substantially greater than the flux observed when the drug is at saturation.
Inventor(s):	Patel; Dinesh C. (Murray, UT), Ebert; Charles D. (Salt Lake City, UT)
Assignee:	Theratech, Inc. (Salt Lake City, UT)
Application Number:	07/626,685
Patent Claims:	1. A device for administering by diffusion a hydrophobic drug transdermally to a patient for a prolonged time period of at least about one day comprising: (a) a reservoir comprising the drug dissolved in a carrier, the amount and solubiilty of the drug in the carrier defining a condition of subsaturation that is sufficient to provide a drug skin flux over at least about 60% of said time period that is at least about 25% greater than the drug skin flux provided when the carrier is saturated with drug; and (b) means for maintaining the reservoir in drug delivery communication with the skin of the patient. 2. The device of claim 1 wherein the reservoir also contains a permeation enhancer. 3. The device of claim 1 wherein the hydrophobic drug has a solubility in water at room temperature <50 .mu.g/ml. 4. The device of claim 1 wherein the hydrophobic drug is estradiol, progesterone, testosterone, norethindrone acetate, or medroxyprogesterone acetate. 5. The device of claim 1 wherein the prolonged time period is 1 to 14 days. 6. The device of claim 1 wherein the carrier is a solid and is a polyacrylate, polymethacrylate, silicone polymer, polyalkyloxide, natural rubber or synthetic rubber. 7. The device of claim 1 wherein the carrier is a fluid and is an alcohol, an alcohol-water mixture, or a low molecular weight polymer. 8. The device of claim 1 wherein the solubility of the drug in the carrier is in the range of 1 to 500 mg/ml. 9. The device of claim 1 wherein the drug skin flux over at least about 60% of the time period is 25% to 400% greater than the drug skin flux provided when the carrier is saturated with drug. 10. The device of claim 1 wherein the concentration of drug in the carrier is about 20% to about 80% the saturation concentration of drug in the carrier over at least about 60% of the time period. 11. The device of claim 1 wherein said means is the carrier and the carrier is an adhesive. 12. The device of claim 1 wherein said means is a basal adhesive layer underlying the reservoir, an adhesive overlay, or a ring of adhesive that is peripheral to the reservoir and is interconnected to the reservoir. 13. In a method of administering by diffusion a hydrophobic drug transdermally to a patient for a prolonged time period of at least about one day by placing a reservoir comprising the drug dissolved in a carrier in communication with the skin of the patient the improvement comprising having the concentration of drug in the carrier at below saturation at the start of the period and maintaining subsaturation thereafter for at least about 60% the time period whereby the flux of the drug through the skin over at least about 60% of the time period is at least about 25% greater than the flux of drug provided when the carrier is saturated with drug. 14. The method of claim 13 wherein the hydrophobic drug is estradiol, progesterone, testosterone, norethindrone acetate, or medroxy progesterone acetate. 15. The method of claim 13 wherein the carrier is a solid and is polyacrylate, polymethacrylate, silicone polymer, polyalkyloxide, natural rubber or synthetic rubber. 16. The method of claim 13 wherein the carrier is a fluid and is an alcohol, an alcohol-water mixture, or a low molecular weight polymer. 17. The method of claim 13 wherein the concentration of drug in the carrier is maintained at 20% to 80% of saturation concentration over at least about 60% of the time period. 18. A method of increasing the flux of a hydrophobic drug from a reservoir of the drug dissolved in a carrier that is in drug delivery communication with an area of unbroken skin of a patient for a prolonged time period of at least about one day above the flux provided when the concentration of drug in the carrier is at saturation comprising having the concentration of drug in the carrier at below saturation at the start of the period and maintaining subsaturation thereafter for at least about 60% of the time period to provide an increase in the flux of at least about 25% greater than the flux of drug provided when the carrier is saturated with drug over at least about 60% of the time period. 19. The method of claim 18 wherein the hydrophobic drug is estradiol, progesterone, testosterone, norethindrone acetate, or medroxyprogesterone acetate. 20. The method of claim 18 wherein the carrier is a polyacrylate, polymethacrylate, silicone polymer, polyalkyloxide, natural rubber or synthetic rubber. 21. The method of claim 18 wherein the carrier is a fluid and is an alcohol, an alcohol-water mixture, or a low molecular weight polymer. 22. The method of claim 18 wherein the concentration of drug in the carrier is maintained at 20% to 80% of saturation concentration over at least about 60% of the time period.