Alginate microparticles for Polymyxin B Peyer's patches uptake: microparticles for antibiotic oral administration

Microparticles with size less than 3 mum, able to be taken up by M cell of Peyer's patches for the drug delivery to the Gut Associated Limphoid Tissue (GALT). were developed in order to improve oral bioavailability of Polymyxin B (PMB). Less than 3 mum alginate microparticles resistant to gastro-intestinal media were prepared by. spray-drying technique and cross-linking by calcium ions and chitosan. The cross-linked microparticles,were evaluated for PMB content by spectrophotometric method, alginate/PMB interaction by rheological study. cross-linking degree by EDS analysis and PMB activity by microbiological assay. By modulating the polymer cross-linking degree, cationic PMB interacted on alginate chains leading to a proper PMB loading as well as antibiotic retention in gastric environment and sustained delivery in intestinal fluid. Moreover, the procedure resulted suitable for PMB biological activity preservation.