The invention provides a drug delivery device for latanoprost or latanoprost acid. The device has a core of latanoprost or latanoprost acid which is surrounded by an internal and external sheath. The external sheath has a first cap that is permeable to latanoprost or latanoprost acid. The first cap may comprise polyvinyl alcohol (PVA), and the PVA may be heat cured. In certain aspects, there are one or more additional caps on the ends of the sheaths formed from one or more polymers. In certain aspects, one or more portions of the drug delivery device is substantially impermeable to latanoprost or latanoprost acid. In certain aspects, the latanoprost or latanoprost acid elutes through the first cap into a biological environment. The invention further provides methods for manufacturing the drug delivery device.
