Controlled release and bioactivity of the monoclonal antibody rituximab from a porous matrix: A potential in situ therapeutic device

• A proof of concept of novel therapeutic device for release of active therapeutic antibodies is presented.
• Extended and controlled release for 30 days is demonstrated.
• Biological activity of the released antibody is demonstrated in cell culture.

We report on a platform for extended release of biologically-active therapeutic antibodies. Extended antibody release has been achieved by utilising a plasma polymer film of controlled and predetermined thickness deposited on the top of a porous platform loaded with rituximab. Antibody release kinetics directly correlates to the plasma polymer film thickness that is in turn controlled by the plasma polymer deposition time. After 1 month, 82%, 60% and 45% of the antibody is released from platforms coated with plasma polymer for 50 s, 150 s and 300 s, respectively. Activity of the released antibody was assessed in cultures of CD20-positive Daudi cells by using polyacrylamide gel electrophoresis and flow cytometry. The results from gel electrophoresis and flow cytometry indicate that the antibody had maintained its integrity during the release process. This work provides a proof-of-concept technology that achieves extended release of biologically active rituximab for more than 30 days.