(4io) Ionic Liquid-Based Drug Delivery Systems for Subcutaneous Administration of High Concentration Monoclonal Antibodies

Drug Delivery , Ionic Liquids , Nanotherapeutics, Macrophage immunology , Cancer immunology , Inflammation, Protein biologics

Teaching interests

Immunoengineering , Drug Delivery , Bio transport , Biofluid Dynamics

Abstract

Subcutaneous administration of high concentration antibody solutions is a promising strategy for enhanced therapeutic outcomes, but challenges persist in achieving efficient delivery due to viscosity and stability issues. For instance, high concentration antibody solutions of concentrations >100mg/ml are often highly viscous due to accelerated protein aggregation and protein unfolding aided by undesirable protein-protein interactions. Injection of highly unstable viscous solutions can cause low absorption rates in the subcutaneous space, leading to delayed onset of action. High viscosity solutions may cause injection site reactions or difficulties with administration and cause localized reactions such as pain, erythema, or swelling at the injection site. High concentration antibody delivery is patient compliant as it often requires fewer and less frequent doses, making treatment more manageable and less disruptive to daily life. This approach can also improve health disparities by enhancing access to effective treatments in underserved communities, where healthcare resources and consistent medical care are often limited.

Ionic liquids (ILs) offer a promising avenue for addressing these challenges. Ionic liquids are salts composed entirely of ions, typically with melting points below 100°C. They are versatile solvents with unique properties, finding applications in various fields. Charge shielding properties ionic liquids prevents protein-protein interactions by neutralizing charges, reducing electrostatic attractions between antibodies, thus preserving their stability and bioactivity. This study investigates the feasibility and efficacy of a novel class of IL-based delivery system synthesized from amino acid precursors for subcutaneous administration of high concentration antibody solutions.

Amino acid-based ionic liquids (AAILs) are superior due to biodegradability, low toxicity, and tunable properties. Derived from natural sources, they offer safety and environmental benefits. Customizable for specific applications, AAILs exhibit high thermal stability and versatility. We synthesized a library of novel amino acid-based IL formulations compatible with high concentration IgG antibodies and evaluated its physicochemical properties, including viscosity, conductivity, and stability. Through rheological analysis, we determined the optimal IL concentration to minimize viscosity while maintaining stability of the antibody solution.

In vitro studies demonstrated the compatibility of the IL formulation with enhancing antibody stability and bioactivity. We found that these ionic liquids formulations could stabilize high concentration in extended stress conditions of increased temperature, concentration, and mechanical stresses with minimal loss in bioactivity. IgG formulated with the IL retained effective binding after extended exposure to high temperatures of 37^oC and 50^oC (Figure 1A and 1B) High concentration antibodies that remain stable under high temperatures eliminate the need for cold chain storage, making them especially beneficial for use in low-resource settings where such facilities are scarce Furthermore, we assessed the cytotoxicity profile of the IL formulation to ensure safety for subcutaneous administration.

In vivo experiments in animal models evaluated the pharmacokinetics and tissue distribution of high concentration IgG (100mg/ml) delivered subcutaneously using the IL formulation compared to conventional delivery of IgG using saline. Our results indicated enhanced bioavailability and prolonged circulation time of antibodies delivered via the IL-based system, with improved tissue penetration and reduced systemic toxicity. Interestingly, we observed a total bioavailability of 83% when using a IL-based subcutaneous delivery system, an almost 2 fold increase when compared to traditional subcutaneous delivery systems, which was shown to have a bioavailability of 47% ( Figure 2)

Overall, our findings highlight the potential of ILs as a versatile platform for the efficient subcutaneous delivery of high concentration antibody solutions, offering opportunities for enhanced therapeutic efficacy and patient compliance in the treatment of various diseases. Further optimization and translational studies are warranted to advance the clinical application of this promising delivery strategy.

Figure Captions:

Figure 1: Binding Affinity of IgG retained after exposure to temperatures of A) 37⁰C and B) 50⁰C for extended time points with and without IL

Figure 2: Time dependent serum bioavailability of subcutaneous IgG formulations ( With and without IL) and total cumulative bioavailability at the end of 21d ( Insert)