Self-contained heating unit and drug-supply unit employing same

A heating unit comprising:

• a) an enclosure comprising a substrate having an exterior surface and an interior surface, wherein the substrate has a thickness in the range of 0.001 to 0.020 inches;
• b) a layer of solid fuel covering an area of the interior surface of the substrate corresponding to an area of the exterior surface of the substrate to be heated, wherein the solid fuel layer has a thickness in the range of 0.001 to 0.030 inches and wherein the solid fuel is configured to heat a portion of the exterior surface of the at least one substrate to a temperature of at least 200° C. within 1 second follow ignition of the solid fuel;
• and
• c) an igniter disposed at least partially within the enclosure for igniting the solid fuel.