Compactable self-sealing drug delivery agents

Active agents comprising coated pellets which self seal if they are damaged are described. More specifically, an active agent, or bead coated with an active agent, is coated with a rate-release controlling polymer and a hydrophilic gel-forming material which forms a gel upon hydration. If the bead is compressed into a solid compact which damages the polymer coating, the hydrophilic substance gels upon exposure to an aqueous environment. The gel provides sufficient sealing of the damaged area in the polymer so that a useful control of drug release is retained in spite of the damage to the polymer. The pellets of the invention exhibit improved flow and compactability. The compacts can be formulated to disintegrate in the gastrointestinal tract, and also may result in either controlled release or immediate release of the active agent.