Microparticulate polyelectrolyte complexes for gentamicin transport across intestinal epithelial

Polysaccharide microparticles for the oral administration of gentamicin were designed in order to obtainan increased drug absorption by means of microparticle transport across the intestinal epithelia. Alginate/chitosan microparticles with a size of ∼ 2 μm were developed by spray-drying a water solution containingthe drug complexed with the polyanionic alginate and subsequent alginate cross-linking process bycalcium ions and chitosan. The pre-formulation study, performed by changing the concentration of bothcross-linkers, led to the selection of the most suitable formulation which was assayed for its capacity to be translocated across intestinal epithelia, via both M cells contained in Follicle Associated Epithelium (FAE) ofPeyer’s patches and enterocytes of the mucosal epithelium. An ex vivo perfusion technique of rabbit andrat intestinal tissues containing Peyer’s patches combined with an in vitro method by using Caco-2 cellmonolayers demonstrated the microparticulate carrier ability to be taken up by both M cells and enterocytes.However, only the endocytosis by M cells appeared to provide the microparticle transport from theepithelium toward deeper sub-epithelial regions.