A dermal drug delivery system is provided which comprises at least two components, for example, a sheet of a solid and flexible material, and a vehicle liquid comprising a solvent and optionally other ingredients. A drug, which can be unstable in said solvent but needs the solvent for being delivered into the skin, can be impregnated in the sheet. Other ingredients, such as agents for fastening the drug on the sheet can also be impregnated in the sheet. These two components may be stored separately and joined either shortly before or at the time of application. To use the system, the vehicle liquid may be applied either on the target skin area or on the sheet, and the sheet may then be applied on the target skin area so that the vehicle liquid is positioned between the sheet and the skin and brought into contact with the ingredients impregnated in the sheet. After the sheet and the vehicle liquid are combined in this way, the ingredients in the sheet and in the vehicle liquid are joined to form a combined formulation that is capable of delivering a drug through the skin at a desired rate. The sheet may have low enough permeability to the solvent or its vapor to control the time it takes for the solvent to evaporate across the sheet. When an appropriate local anesthetic agent, such as a tetracaine, is the drug, some embodiments of the system can have wide applications in anesthesia and pain control.
