Methods of controlling uniformity of substrate temperature and self-contained heating unit and drug-supply unit employing same

Abstract

Methods for rapid heating while controlling the uniformity of temperature of a substrate and peak temperatures are disclosed. Heating units, drug supply units and drug delivery articles employing these methods are disclosed. Rapid heating is obtained by use of a solid fuel capable of undergoing an exothermnic metal oxidation reaction disposed within the substrate are disclosed. Drug supply units and drug delivery articles wherein a solid fuel is configured to heat a substrate to a temperature sufficient to rapidly thermally vaporize a drug disposed thereon are also disclosed.

What is claimed is:  
     
         1 . A method of controlling uniformity of temperature and peak temperature of an exterior surface of a rapidly heated substrate comprising coating a thin layer of an essentially homogenous slurry of a selected mass of a solid fuel, which comprises an metal-containing oxidizing agent and a reducing agent in a defined ratio, on a portion of an interior surface of the substrate to be heated.  
     
     
         2 . The method of  claim 1 , wherein said coating is a dip coating, spray coating, roller coating, gravure coating, reverse roll coating, gap coating, metering rod coating, slot die coating, curtain coating, and air knife coating.  
     
     
         3 . The method of  claim 2 , wherein said gap coating is done with a wire wound coating rod.  
     
     
         4 . The method of  claim 1 , wherein the peak temperature of the substrate upon heating is controlled by selecting and coating a mass of solid fuel determined to give that peak temperature.  
     
     
         5 . The method of  claim 1 , wherein the substrate is selected from a metal, an alloy, and a ceramic.  
     
     
         6 . The method  claim 5 , wherein the substrate is a metal foil.  
     
     
         7 . The method of  claim 6 , wherein the metal foil exhibits a thickness ranging from 0.001 inches to 0.010 inches.  
     
     
         8 . The method of  claim 1 , wherein the thin layer of solid fuel exhibits a thickness ranging from 0.001 inches to 0.030 inches.  
     
     
         9 . The method of  claim 1 , wherein the thin layer of solid fuel exhibits a thickness ranging from 0.001 inches to 0.005 inches.  
     
     
         10 . The method of  claim 1 , wherein the metal containing oxidizing agent is selected from at least one of the following MoO 3 , KClO 4 , KClO 3 , and Fe 2 O 3 .  
     
     
         11 . The method of  claim 1 , wherein the metal reducing agent is selected form at least one of the following: aluminum, zirconium, iron, and titanium.  
     
     
         12 . The heating unit of  claim 1 , wherein the amount of metal reducing agent ranges from 60% by weight to 90% by weight of the total dry weight of the solid fuel.  
     
     
         13 . The heating unit of  claim 1 , wherein the amount of metal-containing oxidizing agent ranges from 10% by weight to 40% by weight of the total dry weight of the solid fuel.  
     
     
         14 . The heating unit of  claim 1 , wherein the solid fuel comprises at least one additive material.  
     
     
         15 . The method of  claim 14 , wherein said additive material is an inorganic material.  
     
     
         16 . The method of  claim 15 , wherein the inorganic material is selected from the group consisting of clays, metal alkoxides, sodium silicates, potassium silicates, aluminum silicates, alumina, silica based sol and inorganic sol-gel material.  
     
     
         17 . The method of  claim 16 , wherein the clay is selected from the group consisting of: Laponite, Montmorillonite, and Cloisite.  
     
     
         18 . A method for providing an essentially homogenous and uniform coating of dry solid fuel on a surface of a substrate comprising: 
 a. mixing a solid fuel, comprising at least one oxidizing agent and at least one reducing agent, with an additive material in a solvent to form a homogenous slurry;    b. coating a thin layer of the slurry at a set thickness on an surface of a substrate; and    c. drying the coated slurry to form a dry solid fuel on the substrate.    
     
     
         19 . The method of  claim 18 , wherein said coating is dip coating, spray coating, roller coating, gravure coating, reverse roll coating, gap coating, metering rod coating, slot die coating, curtain coating, and air knife coating.  
     
     
         20 . The method of  claim 19 , wherein said gap coating is done with a wire wound coating rod in a bar coater.  
     
     
         21 . The method of  claim 18 , wherein prior to coating a mask is positioned on a portion of the surface of the substrate to prevent deposition of the solid fuel on said portion.  
     
     
         22 . The method  claim 18 , wherein the substrate is a metal foil.  
     
     
         23 . The method of  claim 22 , wherein the metal foil exhibits a thickness ranging from 0.001 inches to 0.010 inches.  
     
     
         24 . The method of  claim 18 , wherein the thin layer of solid fuel exhibits a thickness ranging from 0.001 inches to 0.030 inches.  
     
     
         25 . The method of  claim 18 , wherein the thin layer of solid fuel exhibits a thickness ranging from 0.001 inches to 0.005 inches.  
     
     
         26 . The method of  claim 18 , wherein the metal containing oxidizing agent is selected from at least one of the following MoO 3 , KClO 4 , KClO 3 , and Fe 2 O 3 .  
     
     
         27 . The method of  claim 18 , wherein the metal reducing agent is selected from at least one of the following: aluminum, zirconium, iron, and titanium.  
     
     
         28 . The method of  claim 18 , wherein said additive material is an inorganic material.  
     
     
         29 . The method of  claim 18 , wherein the additive material is Laponite.  
     
     
         30 . The method of  claim 18 , wherein said drying is in an oven for at least two hours.  
     
     
         31 . A heating unit that upon firing rapidly heats a defined area of an exterior surface of a substrate to an essentially uniform temperature and a set peak temperature comprising: 
 a. an enclosure comprising at least one substrate having an exterior surface and an interior surface,    b. an essentially homogenous and thin layer of solid fuel coated on the interior surface of the substrate corresponding to the defined area of the exterior surface of the substrate to be heated; and    c. an igniter disposed within the enclosure for igniting the solid fuel.    
     
     
         32 . The heating unit of  claim 31 , wherein the peak temperature is set by the mass of solid fuel coated on the interior surface of the substrate.  
     
     
         33 . The method of  claim 31 , wherein the thin layer of solid fuel exhibits a thickness ranging from 0.001 inches to 0.030 inches.  
     
     
         34 . The method of  claim 31 , wherein the thin layer of solid fuel exhibits a thickness ranging from 0.001 inches to 0.005 inches.  
     
     
         35 . The method of  claim 31 , wherein the enclosure comprises more than one substrate.  
     
     
         36 . The method of  claim 31 , wherein the substrate is a metal foil.  
     
     
         37 . The method of  claim 31 , wherein the metal containing oxidizing agent is selected from at least one of the following MoO 3 , KClO 4 , KClO 3 , and Fe 2 O 3 .  
     
     
         38 . The method of  claim 31 , wherein the metal reducing agent is selected from at least one of the following: aluminum, zirconium, iron, and titanium.  
     
     
         39 . The method of  claim 31 , wherein the solid fuel comprises at least one additive material.  
     
     
         40 . The method of  claim 39 , wherein the additive material is Laponite.