A method and apparatus for delivering a therapeutic and/or diagnostic agent to tissue within a bodily cavity is provided herein. The apparatus may include a catheter assembly including a catheter and a delivery balloon having an expandable material disposed thereon, wherein the expandable material may be an absorbent at least partially charged with a therapeutic and/or diagnostic agent. The method may include the step of delivering a therapeutic and/or diagnostic agent to tissue by inflating the delivery balloon by supplying fluid thereto until the expandable material adopts an expanded state in which the expandable material contacts the tissue and is implanted in a bodily cavity.
