Aerosolization of poly(sulfobetaine) microparticles that encapsulate therapeutic antibodies

Pulmonary delivery of protein therapeutics poses significant challenges that have not been well addressed in the research literature or practice. In fact, there is currently only one commercial protein therapeutic that is delivered through aerosolization and inhalation. In this study, we propose a drug delivery strategy that enables a high-concentration dosage for the pulmonary delivery of antibodies as an aerosolizable solid powder with desired stability. We utilized zwitterionic polymers for their promising properties as drug delivery vehicles and synthesized swellable, biodegradable poly(sulfo-betaine) (pSB) microparticles. The microparticles were loaded with Immunoglobulin G (IgG) as a model antibody. We quantified the microparticle size and morphology, and the particles were found to have an average diameter of 1.6 μm, falling within the optimal range (~1-5 μm) for pulmonary drug delivery. In addition, we quantified the impact of the crosslinker to monomer ratio on particle morphology and drug loading capacity. The results showed that there is a trade-off between desired morphology and drug loading capacity as the crosslinker density increases. In addition, the particles were aerosolized, and our data indicated that the particles remained intact and retained their initial morphology and size after aerosolization. The combination of morphology, particle size, antibody loading capacity, low cytotoxicity, and ease of aerosolization support the potential use of these particles for pulmonary delivery of protein therapeutics.

UV-Crosslinked Poly(N-isopropylacrylamide) Interpenetrated into Chitosan Structure with Enhancement of Mechanical Properties Implemented as Anti-Fouling Materials

High-performance properties of interpenetration polymer network (IPN) hydrogels, based on physically crosslinked chitosan (CS) and chemically crosslinked poly(N-isopropylacrylamide) (PNiPAM), were successfully developed. The IPN of CS/PNiPAM is proposed to overcome the limited mechanical properties of the single CS network. In this study, the viscoelastic behaviors of prepared materials in both solution and gel states were extensively examined, considering the UV exposure time and crosslinker concentration as key factors. The effect of these factors on gel formation, hydrogel structures, thermal stabilities of networks, and HeLa cell adhesion were studied sequentially. The sol-gel transition was effectively demonstrated through the scaling law, which agrees well with Winter and Chambon's theory. By subjecting the CS hydrogel to the process operation in an ethanol solution, its properties can be significantly enhanced with increased crosslinker concentration, including the shear modulus, crosslinking degree, gel strength, and thermal stability in its swollen state. The IPN samples exhibit a smooth and dense surface with irregular pores, allowing for much water absorption. The HeLa cells were adhered to and killed using the CS surface cationic charges and then released through hydrolysis by utilizing the hydrophilic/hydrophobic switchable property or thermo-reversible gelation of the PNiPAM network. The results demonstrated that IPN is a highly attractive candidate for anti-fouling materials.