A transdermal patch that can easily deliver a controlled volume of a fluidic drug compound to the skin is provided. More particularly the patch contains a microneedle assembly that is configured to be placed in fluid communication with a drug delivery assembly. The microneedle assembly contains a support and a plurality of microneedles that extend outwardly from the support. The microneedles are formed with one or more channels of a certain dimension such that passive capillary flow drives the flow of the drug compound. The drug delivery system contains a reservoir for the drug compound that is in fluid communication with a rate control membrane that helps control the flow rate of the drug compound by modulating its pressure downstream from the reservoir. A release member is also positioned adjacent to the microneedle and drug delivery assemblies. Prior to use the release member acts as a barrier to the flow of the drug compound and thus inhibits premature leakage. In this manner the patch can initially be provided in an "inactive" configuration in which the drug compound is securely retained. When it is desired to release the drug compound the patch can simply be activated by at least partially separating the release member from the drug delivery and microneedle assemblies.
