(543f) Controlled Delivery of Functional Antibody From Amphiphilic Polyanhydride Nanoparticles

The most widely used type of passive immunotherapy involves the administration of antibodies (e.g., monoclonal antibodies) to patients to provide immunity against disease, or help fight off infections. For example, it has been suggested that antibodies could be used in early, passive immune treatments for HIV and the passive transfer of IgG has also been shown to protect against Ebola in mice. As with the development of protein pharmaceutics, one of the most challenging tasks in passive immunotherapies is to deal with the physical and the chemical instabilities of the protein (i.e., antibodies), which invariably leads to loss of biological activity. In order to avoid these problems, it is necessary to design delivery vehicles that will minimize the degradation, maximize the in vivo activity, and provide controlled release of the encapsulated protein.

Biodegradable polyanhydrides have been shown to stabilize and provide sustained release of proteins to be used in vaccine formulations. However, the mechanisms of protein alteration are protein-specific, so it is necessary to select polymer formulations that can stabilize the specific protein of interest. In this study, the use of polyanhydride nanoparticles is suggested for the delivery of two antibodies in order to show their ability to release stable therapeutic payloads. Tetanus anti-toxin and anti-TNF-α monoclonal antibody were encapsulated and released from polyanhydride nanoparticles fabricated by an anti-solvent nanoencapsulation method. The polyanhydride systems based on copolymers of 1,6-bis(p-carboxyphenoxy)hexane (CPH), sebacic acid (SA), and 1,8-bis(p-carboxyphenoxy)-3,6-dioxacotane (CPTEG) monomers were used in this work. In vitro release kinetics were evaluated at physiological conditions and quantified using the micro-bicinchonic acid assay. Enzyme-linked immunosorbent assay (ELISA) was used to quantify the antigenicity of both the full tetanus anti-toxin and the monoclonal anti-TNF-α after release from polyanhydride nanoparticles. A biological assay was used to determine the biological function of the released anti- TNF-α by measuring their neutralization ability to the killing effect of TNF- α in L929 cells. Experiments were also performed to determine the effect of nanoparticle chemistry on the primary, secondary, and tertiary structure of the released protein. Results indicated that the amphiphilic environment provided by CPTEG-containing polyanhydrides preserved protein antigenicity, suggesting that this platform can be effectively used as a delivery system for therapeutic proteins.