Biodistribution assessment of cationic pullulan nanogel, a nasal vaccine delivery system, in mice and non-human primates

Cationic cholesteryl-group-bearing pullulan nanogel (cCHP-nanogel) is an effective drug-delivery system for nasal vaccines. However, cCHP-nanogel-based nasal vaccines might access the central nervous system due to its close proximity via the olfactory bulb in the nasal cavity. Using real-time quantitative tracking of the nanogel-based nasal botulinum neurotoxin and pneumococcal vaccines, we previously confirmed the lack of deposition of vaccine antigen in the cerebrum or olfactory bulbs of mice and non-human primates (NHPs), rhesus macaques. Here, we used positron emission tomography to investigate the biodistribution of the drug-delivery system itself, cCHP-nanogel after mice and NHPs were nasally administered with 18F-labeled cCHP nanogel. The results generated by the PET analysis of rhesus macaques were consistent with the direct counting of radioactivity due to 18F or 111In in dissected mouse tissues. Thus, no depositions of cCHP-nanogel were noted in the cerebrum, olfactory bulbs, or eyes of both species after nasal administration of the radiolabeled cCHP-nanogel compound. Our findings confirm the safe biodistribution of the cCHP-nanogel-based nasal vaccine delivery system in mice and NHPs.& COPY; 2023 The Author(s). Published by Elsevier Ltd.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Using real-time quantitative tracking technology, positron emission tomography analysis was conducted to investigate the biodistribution of the drug-delivery system cCHP-nanogel in mice and non-human primates. The results confirmed that no depositions of cCHP-nanogel were observed in the cerebrum, olfactory bulbs, or eyes after nasal administration, indicating the safe biodistribution of the cCHP-nanogel-based nasal vaccine delivery system.