A nanocomposite delivery system uses chitosan as a mucoadhesive material encapsulated in a surface modified network of colloidal nanoporous nanoparticles, such as silica, or other colloid-forming materials, especially metal oxides. Drug delivery systems may be provided by binding a drug to the chitosan/silica nanocomposite, typically by adding a drug or other active agent during in-situ gellation of colloidal silica. When the active agent is, for example, amoxicillin or other antibiotic agent, the drug delivery system may be used in the treatment of stomach ulcers, for example.