Nano-in-nano enteric protein delivery system

SONZOGNI, ANA SOFÍA; RIVERO GUADALUPE; GONZALEZ, VERÓNICA; ABRAHAM, GUSTAVO A.; MINARI, ROQUE; CALDERÓN, MARCELO

Mar del Plata

Congreso; XII Latin-American Congress of Artificial Organs and Biomaterials; 2023

INTEMA

Introduction and objective: Oral protein delivery holds significant promise as an effective therapeutic strategy for treating a wide range of diseases. However, effective absorption of proteins faces challenges due to biological barriers such as harsh conditions of the stomach and the low permeability of mucous membranes. To address these challenges, we present a novel nano-in-nano platform for enteric protein delivery in this work. This platform involves a coaxial arrangement comprising poly(N-vinylcaprolactam) nanogels (NGs) enclosed within nanofibers of Eudragit®L100-55 (EU). The pH-selective solubility of EU ensures NGs protection in the stomach, where fibers remain intact, and it releases them in the intestine where EU dissolves. [1]Methodology: NGs were synthesized with N-vinylcaprolactam and N,N-methylenebisacrylamide as crosslinker in batch emulsion polymerization. Nano-in-nano platform was prepared by coaxial electrospinning with a NGs concentration of 10 mg/mL. Compositional and processing parameters were optimized, including the evaluation of EU concentrations of 150 and 200 mg/mL, different solvents and flow rates for both components and voltage. The membranes were exposed to different media, to simulate gastrointestinal tract conditions. In each environment, both the morphology and the protein release were evaluated. Results and discussion: Thermoresponsive NGs, suitable size for biological applications, were successfully encapsulated within electrospun coaxial fibers. They have a collapsed size of 142.9 nm (PDI 0.058) and a transition temperature of 32.5 °C, and they were capable to host a model protein (ovalbumin, OVA) with a loading capacity of 0.963 mgOVA/mgNGs and temperature-dependent release. Degradation kinetics of the fibers show that at stomach pH, fibers lost approximately 20% of their weight, while in PBS (pH = 6.8) membranes were completely degraded after 2 h of incubation. Also, the degradation kinetic strongly depends on the EU content and on the presence of NGs. Membranes with lower EU content dissolved earlier, and for the same EU concentration, those with NGs took longer to dissolve. OVA release profiles were studied by incubating fibers for 2 h in HCl 0.1N and then incubating in PBS pH 6.8 until complete dissolution. In all cases, OVA release in HCl 0.1 N is lower than 10%, indicating that OVA is retained in the nano-in-nano system during 2 h equivalent residence time in the stomach. As expected, once the fibers were exposed to pH 6.8, they dissolved slower when containing larger EU content and NGs cargo.Conclusions: This designed nano-in-nano system demonstrated pH-responsive behavior, enabling the controlled release of NGs with a kinetic profile suitable for therapeutic enteric treatments. It effectively protected the protein cargo in the stomach’s acidic environment and facilitated its release in the duodenum at pH 6. The ability to modify the release profile simply by adjusting the concentration of EU used in the electrospinning process shows the potentiality of this nano-in-nano delivery platform.References [1] M. Vlachou et al., Pharmaceutics, 11, 1–13, 2019.