Disclosed herein are delivery systems including coated and uncoated yarns, yarn precursors, threads, fibers, and other substrates for the constant or near-constant release of active compounds, as well as methods for manufacturing such delivery systems. The yarns, yarn precursors, threads, fibers, and other substrates can include a cross-linked hydrophobic elastomer and an active compound. One or more coatings that are impermeable or substantially impermeable to the active compound may partially or fully occlude the yarn or substrate to control release rates of the active compound. The delivery systems may be used in a variety of applications, including the making of articles of clothing, textiles, and fabrics, and may be used in methods of treating various conditions and diseases.