One of the technologies of DURECT is the DUROS® implant technology, coupled with proprietary drug delivery catheter and drug formulation technology. DURECT licensed the DUROS® technology for selected fields from ALZA Corporation in 1998. ALZA's Viadur® (leuprolide acetate implant) is the first approved product to be administered via the DUROS® System. The product was approved by the Food and Drug Administration in March 2000 as a palliative treatment for prostate cancer.

The DUROS® pump operates like a miniature syringe loaded with a drug inside the drug reservoir. Through osmosis, water from the body is slowly drawn through a semipermeable membrane into the pump by salt residing in the engine compartment. This water fills the pump, which slowly and continuously pushes a piston, dispensing the correct amount of drug out of the drug reservoir and into the body. The osmotic engine does not require batteries, switches or other electromechanical parts in order to operate. The amount of drug delivered by the system is regulated by the membrane's control over the amount of water entering the pump and by the concentration of the drug in the drug reservoir.

Certain performance characteristics of the DUROS® system cannot be matched by drug delivery pumps on the market today. First, the pump can generate sufficient pressure to deliver highly concentrated and viscous formulations. Second, the system can be engineered to deliver a drug dosage at the desired dosing rate with a high degree of precision, to less than 1/100th of a drop per day on a continual basis. The titanium shell of the DUROS® system protects the drug formulation from degradation by enzymes and its passage through the body. As a result, the DUROS® system can store and release drugs in the body for up to one year.

The DUROS® system can be used for therapies requiring systemic or site-specific administration of a drug. To deliver drugs systemically, the DUROS® system is placed just under the skin, for example in the upper arm, in an outpatient procedure that is completed in just a few minutes using local anesthetic. Removal or replacement of the product is also a simple, quick procedure completed in the doctor's office.

To deliver a drug to a specific site, DURECT is developing proprietary miniaturized catheter technology that can be attached to the DUROS® system to direct the flow of a drug to the target organ, tissue or synthetic medical structure, such as a graft. Site specific delivery enables a therapeutic concentration of a drug to be administered to the desired target without exposing the entire body to a similar dose. The precision, size and performance of the DUROS® system will allow for continuous site-specific delivery to a variety of precise locations within the body.

For more information, download the DUROS® Fact Sheet (.PDF)