A drug delivery system which comprises alginate tube that is prepared by coating a substrate with alginate gel. One or more therapeutic drugs may also be present in the alginate gel or in the cavity of the tube. The activity of the alginate drug delivery system is highly adjustable so that the release may be controlled as required. The rate at which the system releases the drug and the concentration of the drug released can be adjusted by varying the number of layers of the alginate tubes, the number of open or closed ends of the tubes, or the number of tube layers containing the drug.
