Stability and Structure of Protein−Lipoamino Acid Colloidal Particles: Toward Nasal Delivery of Pharmaceutically Active Proteins

摘要

To circumvent the painful intravenous injectionnof proteins in the treatment of children with growth deficiency,nanemia, and calcium insufficiency, we investigated the stabilitynand structure of protein−lipoamino acid complexes that couldnbe nasally sprayed. Preparations that ensure a colloidal andnstructural stability of recombinant human growth hormonen(rhGH), recombinant human erythropoietin (rhEPO), andnsalmon calcitonin (sCT) mixed with lauroyl proline (LP) werenestablished. Protein structure was controlled by circularndichroism, and very small sizes of ca. 5 nm were determinednby dynamic light scattering. The colloidal preparations could be sprayed with a droplet size of 20−30 μm. The molecularnstructure of aggregates was investigated by all-atom molecular dynamics. Whereas a lauroyl proline capping of globular proteinsnrhGH and rhEPO with preservation of their active structure was observed, a mixed micelle of sCT and lipoamino acids wasnformed. In the latter, aggregated LP constitutes the inner core and the surface is covered with calcitonins that acquire a marked α-nhelix character. Hydrophobic/philic interaction balance between proteins and LP drives the particles' stability. Passage throughnnasal cells grown at confluence was markedly increased by the colloidal preparations and could reach a 20 times increase in thencase of EPO. Biological implications of such colloidal preparations are discussed in terms of furtiveness.