This invention describes a partially absorbable, fiber-reinforced composite in the form of a ring, or a suture-like thread, with modified terminals for use as a controlled delivery system of at least one bioactive agent, wherein said composite comprising an absorbable fiber construct capable of providing time-dependent mechanical properties of a biostable elastomeric matrix containing an absorbable microparticulate ion-exchanger to modulate the release of the bioactive agent(s) for a desired period(s) of time at a specific biological site; this can be a vaginal canal, peritoneal cavity, scrotum, prostate gland, an ear loop or subcutaneous tissue. Such drug delivery systems can be used for the local administration of at least one bioactive agent, including those used as contraceptive, antimicrobial, anti-inflammatory and/or antiviral agents as well as for cancer treatment.