In this presentation, Christian Schneider of Celanese discussed innovations in long-acting parenteral drug delivery, focusing on the use of ethylene vinyl acetate (EVA) as a versatile excipient for sustained release of peptides, antibodies, and RNA. With over a decade of experience in polymer R&D, Schneider highlighted EVA’s long-standing role in drug delivery systems, noting its established regulatory familiarity and commercial use across various routes, including subcutaneous implants, ocular inserts, intravaginal rings, and transdermal patches.
He began by outlining the patient-centric benefits of long-acting dosage forms, such as reduced treatment burden, improved compliance, and increased comfort – particularly valuable in addiction therapies and chronic diseases. Schneider discussed emerging applications where EVA could help overcome biological barriers, such as delivering therapeutics across the blood-brain barrier or targeting localised tumours.
EVA’s key advantage lies in its chemical inertness and thermoplastic nature, allowing for controlled drug release over a wide range – from weeks to several years. This is enabled by tuning its crystallinity through the vinyl acetate content, which directly influences drug permeability. EVA’s compatibility extends across hydrophilic and hydrophobic small molecules, peptides, proteins, monoclonal antibodies, and oligonucleotides, provided the drug is in solid form to withstand the hot melt extrusion process.
Schneider detailed how EVA’s structure supports two primary release mechanisms: diffusion through the polymer matrix for small molecules and porous network release for larger biologics. He presented in vitro release studies confirming predictable and tuneable drug release based on EVA formulation parameters. EVA's flexibility also supports advanced designs, such as core–shell constructs using rate-controlling membranes to achieve near zero-order kinetics – especially beneficial for drugs with narrow therapeutic windows
He showcased successful release profiles for proteins like lysozyme and monoclonal antibodies such as trastuzumab, noting good thermal stability during processing. Additionally, antisense oligonucleotides (ASOs) showed no degradation after extended release studies, underlining EVA’s potential for RNA-based therapeutics.
Finally, Schneider discussed future applications being explored by Celanese and its partners, including subcutaneous and intratumoural delivery for oncology, central nervous system disorders, and ophthalmic uses. He concluded by inviting collaboration and highlighting Celanese’s pharmaceutical-grade EVA supply and development services.
