Multi-unit drug delivery devices and methods

The present invention is directed to devices in which relatively lower solubility drugs can be released at therapeutically useful rates by an osmotic pressure means over an extended period. In a first aspect the invention provides an intravesical drug delivery devices comprising a housing defining a reservoir; a first unit contained within the reservoir in a first position, the first unit comprising a drug; and a second unit contained within the reservoir in a second position distinct from the first position the first and second positions being in fluid communication with one another, wherein the second unit comprises an osmotic agent that facilitates in vivo release of the drug from the housing, and wherein the device is elastically deformable between a relatively straightened shape suited for insertion through the urethra of a patient and into the patient's bladder and a retention shape suited to retain the device within the bladder. The functional agent is an osmotic agent, and the second unit is contained within the reservoir in a second position distinct from a first position of the first unit.