Targeted PEG-poly(glutamic acid) complexes for inhalation protein delivery to the lung

[摘要] Pulmonary delivery is increasingly seen as an attractive, non-invasive route for the delivery of forthcoming protein therapeutics. In this context, here we describe protein complexes with a new 'complexing excipient' vitamin B-12-targeted poly(ethylene glycol)-block-poly(glutamic acid) copolymers. These form complexes in sub200 nm size with a model protein, suitable for cellular targeting and intracellular delivery. Initially we confirmed expression of vitamin B-12 -internalization receptor (CD320) by Calu-3 cells of the in vitro lung epithelial model used, and demonstrated enhanced B-12 receptor-mediated cellular internalization of B-12-targeted complexes, relative to non-targeted counterparts or protein alone. To develop an inhalation formulation, the protein complexes were spray dried adopting a standard protocol into powders with aerodynamic diameter within the suitable range for lower airway deposition. The cellular internalization of targeted complexes from dry powders applied directly to Calu-3 model was found to be 2-3 fold higher compared to non-targeted complexes. The copolymer complexes show no complement activation, and in vivo lung tolerance studies demonstrated that repeated administration of formulated dry powders over a 3 week period in healthy BALB/c mice induced no significant toxicity or indications of lung inflammation, as assessed by cell population count and quantification of IL-1 beta, IL-6, and TNF-alpha pro-inflammatory markers. Importantly, the in vivo data appear to suggest that B-12-targeted polymer complexes administered as dry powder enhance lung retention of their protein payload, relative to protein alone and non-targeted counterparts. Taken together, our data illustrate the potential developability of novel B-12-targeted poly(ethylene glycol)-poly(glutamic acid) copolymers as excipients suitable to be formulated into a dry powder product for the inhalation delivery of proteins, with no significant lung toxicity, and with enhanced protein retention at their in vivo target tissue.

[发布日期] 2019-12-28

[关键词] Polymer-protein complexes;Inhalation delivery;Spray-dried inhalation powder;Protein delivery;Targeted complexes