Validation of Therapeutic Agent Conjugation to Polyvinyl Alcohol-Coated Medical Devices

Protein-based therapeutics are often limited by their route of administration and inability to confine them to their site of action. One innovative approach we have developed is to covalently bind protein therapeutics to medical devices, allowing more localized and highly concentrated delivery of these agents to their intended site of action. This study aims to evaluate if glucagon-like peptide-2 (GLP-2) can be covalently bound to the vaginal expansion sleeve (VES) and intestinal expansion sleeve (IES) devices in clinically relevant and measurable quantities. Expansion sleeves were coated with polyvinyl alcohol (PVA) and crosslinked with glutaraldehyde/sulfuric acid vapor to create a chemically active surface capable of binding amine-containing therapeutics such as GLP-2. A standard curve was created by binding 250 µg, 100 µg, 50 µg, 25 µg, and 0 µg of GLP-2 to PVA-coated wells of a 24-well plate. An ELISA standard was created using a rabbit anti-GLP-2 antibody followed by a goat anti-rabbit IgG alkaline phosphatase secondary antibody plus an alkaline phosphatase blue microwell substrate. Colorimetry (yellow to blue at 620 nm) was proportional to the concentration of GLP-2 bound antibodies, enabling calculation of the bound concentration of GLP-2 on the PVA-coated sleeves. The addition of 50 µg of GLP-2 to IES/VES devices bound an average of 22.69 ± 9.32 µg/cm² of GLP-2 with an external IES/VES surface area (9.425 cm²), indicating that 44% of added GLP-2 was immobilized on the PVA coated IES/VES sleeves. Current human GLP-2 dosing is 50 µg/Kg. Because each sleeve carries 22 µg, this is approximately 44% of a systemic dose in a single device. This methodology makes it possible to add dramatically lower doses of therapeutic agents to get the same effect as systemic administration of the GLP-2 drug while also avoiding systemic effects.