Effect of the Emulsion Solvent Evaporation Technique Cosolvent Choice on the Loading Efficiency and Release Profile of Anti-CD47 from PLGA Nanospheres.

INTRODUCTION: Side effects associated with using antibodies as therapeutics can limit systemic administration at the high concentrations often needed for therapeutic impact. Thus, therapeutic antibodies are usually considered for targeted delivery. Antibody encapsulation in polymeric nanoparticles via the emulsion-based nanofabrication methods typically yields low loading efficiencies. Therefore, the fabrication techniques need to be modified to maximize the loading efficiency of antibodies. In this work, we utilized various cosolvents with the emulsion solvent evaporation technique to improve the loading efficiency of anti-CD47, a therapeutic antibody used to block CD47 activity in atherosclerotic plaques and cancer lesions. METHODS AND RESULTS: The double emulsion solvent evaporation technique was used to fabricate anti-CD47-loaded polymeric nanoparticles. The primary oil phase solvent, chloroform, was doped with different cosolvents, including ethyl acetate, acetonitrile, ethanol, and methanol, to investigate the impact of cosolvents on the loading efficiency of anti-CD47. The release profile and loading efficiency were quantified by measuring the fluorescence signal of the released antibody. The activity of the antibody released from particles fabricated in the presence of the cosolvent was confirmed by quantifying its adherence to red blood cells. Ethyl acetate was the optimum cosolvent, improving the loading efficiency of anti-CD47 in poly(lactic-co-glycolic acid), PLGA, nanoparticles to 90% or higher, and the antibody was found to retain its activity after being released from nanoparticles. CONCLUSION: Our results demonstrate that a minimum amount of a cosolvent with minimal hydrophilicity can stabilize the antibody in the oil phase; thus, improving the antibody's loading efficiency significantly.

Biodegradable, bile salt microparticles for localized fat dissolution.

Bile acids are proposed as therapeutic agents for various diseases, including liver diseases and obesity. However, oral or subcutaneous administration of a solubilized version of these drugs has limited efficacy and imposes unwanted side effects. Here, we describe a gold-templating method for fabricating stable, bile salt-cholate or deoxycholate-microparticles. The gold ions' reduction at the oil-water interface in a double emulsion solvent evaporation process enables a gold-bile salt interaction and the formation of bile salt particles. We demonstrate that composite microparticles release cholate/deoxycholate into solution via a surface erosion process. We illustrate these particles' capability to lyse adipocytes, both in vitro and in vivo, with minimal side effects, contrary to the Food and Drug Administration-approved salt solution that leads to severe inflammation and ulceration. Overall, particle-based cholate/deoxycholate opens opportunities for localized delivery of these salts, improving efficacy while minimizing side effects associated with oral and subcutaneous use.

Neutrophils preferentially phagocytose elongated particles-An opportunity for selective targeting in acute inflammatory diseases.

Polymeric particles have recently been used to modulate the behavior of immune cells in the treatment of various inflammatory conditions. However, there is little understanding of how physical particle parameters affect their specific interaction with different leukocyte subtypes. While particle shape is known to be a crucial factor in their phagocytosis by macrophages, where elongated particles are reported to experience reduced uptake, it remains unclear how shape influences phagocytosis by circulating phagocytes, including neutrophils that are the most abundant leukocyte in human blood. In this study, we investigated the phagocytosis of rod-shaped polymeric particles by human neutrophils relative to other leukocytes. In contrast to macrophages and other mononuclear phagocytes, neutrophils were found to exhibit increased internalization of rods in ex vivo and in vivo experimentation. This result suggests that alteration of particle shape can be used to selectively target neutrophils in inflammatory pathologies where these cells play a substantial role.