GASTRO-RETENTIVE FLOATING DRUG DELIVERY SYSTEMS

A drug delivery device for administering a drug at a controlled rate for a prolonged period of time to produce a local or systemic physiological or pharmacological effect is comprised of a wall surrounding a reservoir containing a drug. The reservoir is formed of a solid drug carrier permeable to the passage of the drug. The wall is formed in at least a part of a microporous material the pores of which contain a drug release rate controlling medium also permeable to the passage of the drug, but the rate of passage of the drug through the medium is lower than the rate passage of the drug through the solid drug carrier so that drug release by the medium in the microporous wall is the drug release rate controlling step for releasing drug from the drug delivery device.