Therapeutic system for administering drugs to the skin
AssigneeAlza Corporation
InventorSantosh K. Chandrasekaran
Life of this patent
Estimating the term…
Abstract
A bandage for administering drugs to the skin that consists of an impermeable backing layer, a drug reservoir layer composed of drug and a carrier, and a contact adhesive layer by which the bandage is adhered to the skin. The contact adhesive layer controls the rate at which drug is administered and maintains that rate at an approximately constant level by virtue of there being a particular correlation between the solubility of the drug in the carrier and in the contact adhesive, the diffusion coefficient of the drug in the carrier and in the contact adhesive, the concentration of drug in the reservoir, and the thickness of the contact adhesive layer.
Claims5
A bandage for administering a drug to the skin or mucosa for a predetermined time period, with t representing a time, in hours, in said time period, consisting essentially of a sandwich type laminate of:
- (a) a backing lamina that is substantially impermeable to the drug, one face of which forms the top of the bandage;
- (b) a drug reservoir lamina adjacent the opposite face of the backing lamina comprising the drug dispersed in a carrier that is permeable to the drug, with the solubility of the drug in the carrier being C.sub.SDR mg/cm.sup.3, the diffusion coefficient of drug in the carrier being D.sub.DR cm.sup.2 /hr, and the concentration of drug in the drug reservoir being C.sub.DR mg/cm.sup.3 ;
- and
- (c) a contact adhesive lamina adjacent and below the drug reservoir lamina comprising a contact adhesive composition that is permeable to the drug, with the thickness of the contact adhesive lamina being l.sub.CA cm, the solubility of the drug in the contact adhesive composition being C.sub.SCA mg/cm.sup.3, the diffusion coefficient of drug in the contact adhesive composition being D.sub.CA cm.sup.2 /hr, and the concentration of drug in the contact adhesive composition being C.sub.CA mg/cm.sup.3, wherein over at least a substantial portion of said time period
- (i) C.sub.CA is not greater than C.sub.SCA, and
- (ii) the ratio ##EQU3## is in the range of about 0.01 to about 0.7.
Dependencies are inferred from the claim text.