title: Stability and structure of protein-lipoamino acid colloidal particles: toward nasal delivery of pharmaceutically active proteins.
abstract: To circumvent the painful intravenous injection of proteins in the treatment of children with growth deficiency, anemia, and calcium insufficiency, we investigated the stability and structure of protein-lipoamino acid complexes that could be nasally sprayed. Preparations that ensure a colloidal and structural stability of recombinant human growth hormone (rhGH), recombinant human erythropoietin (rhEPO), and salmon calcitonin (sCT) mixed with lauroyl proline (LP) were established. Protein structure was controlled by circular dichroism, and very small sizes of ca. 5 nm were determined by dynamic light scattering. The colloidal preparations could be sprayed with a droplet size of 20-30 μm. The molecular structure of aggregates was investigated by all-atom molecular dynamics. Whereas a lauroyl proline capping of globular proteins rhGH and rhEPO with preservation of their active structure was observed, a mixed micelle of sCT and lipoamino acids was formed. In the latter, aggregated LP constitutes the inner core and the surface is covered with calcitonins that acquire a marked α-helix character. Hydrophobic/philic interaction balance between proteins and LP drives the particles' stability. Passage through nasal cells grown at confluence was markedly increased by the colloidal preparations and could reach a 20 times increase in the case of EPO. Biological implications of such colloidal preparations are discussed in terms of furtiveness.
authors.affiliation: Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR 5248, CNRS, Université Bordeaux, Institut Polytechnique Bordeaux, Pessac, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Bijani
authors.forename: Clément
authors.initials: C
authors.lastname: Arnarez
authors.forename: Sabrina
authors.initials: S
authors.lastname: Brasselet
authors.forename: Corinne
authors.initials: C
authors.lastname: Degert
authors.forename: Olivier
authors.initials: O
authors.lastname: Broussaud
authors.forename: Juan
authors.initials: J
authors.lastname: Elezgaray
authors.forename: Erick J
authors.initials: EJ
authors.lastname: Dufourc
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D002478:Cells, Cultured; D003102:Colloids; D006801:Humans; D056004:Molecular Dynamics Simulation; D010316:Particle Size; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry*; D011487:Protein Conformation; D055550:Protein Stability; D011506:Proteins / Q000008:administration & dosage* / Q000737:chemistry*
chemical_list: D003102:Colloids; D011506:Proteins; D011392:Proline; C574090:N-lauroylproline