Abstract: Methods are provided for manufacturing transdermal drug delivery systems containing supersaturated drug reservoirs, such that higher drug fluxes are obtained. The methods involve heating the drug reservoir components to a predetermined temperature. Generally, this temperature is higher than the depressed melting temperature of the polymer-drug admixture which will serve as the drug reservoir. In an alternative embodiment, wherein heat treatment of the reservoir components results in a system having two liquid phases, the predetermined temperature is calculated so as to be higher than the melting temperature of the pure drug. Drug reservoirs and novel transdermal delivery systems prepared using the disclosed techniques are provided as well.