Abstract: A transdermal drug delivery device is disclosed for administering an oxidizably and/or hydrolyzably degradable drug, e.g., cholinesterase inhibitors such as rivastigmine. The device comprises a) a substantially impermeable backing layer; b) an adhesive layer substantially free of antioxidant and containing a therapeutically effective amount of the degradable drug, which adhesive drug-containing layer is capable of adhering directly to a subject's skin or to another adhesive layer which is capable of adhering to a subject's skin; and c) a substantially impermeable protective release liner layer which releasably contacts the adhesive drug-containing layer or another adhesive layer. The delivery device is sealed in a degradation protective packaging system, such as a substantially oxygen impermeable heat sealable plastic pouch that contains a substantially inert gas and/or a degradation protectant material for the drug, such as an antioxidant, which can be inserted separately to the pouch.