title: pH-sensitive microparticles for oral drug delivery based on alginate/oligochitosan/Eudragit(®) L100-55 "sandwich" polyelectrolyte complex.
abstract: The primary objective of this study was to investigate the influence of the oligochitosan-Eudragit(®) L100-55 polyelectrolyte complex (OCH-EL PEC) on the pH-sensitivity of Eudragit(®) L100-55-treated alginate-oligochitosan microparticles. In order to achieve this, three types of naproxen-loaded microparticles were prepared under mild and environmentally friendly conditions using a custom made device with coaxial air flow: Ca-alginate (Ca-ALG), alginate-oligochitosan (ALG-OCH) and alginate-oligochitosan-Eudragit(®) L100-55 (ALG-OCH-EL) microparticles. After drying, the microparticles were subjected to microscopic analysis, and physicochemical and biopharmaceutical characterization. The non-covalent interaction between OCH and EL and the formation of OCH-EL PEC during the preparation procedure of the particles were verified by thermal and FT-IR analysis. The obtained particles exhibited acceptable sphericity and surface roughness due to the presence of the drug crystals (Ca-ALG particles) and OCH-EL PEC (ALG-OCH-EL particles). It was found that reinforcement of the ALG-OCH particles with OCH-EL PEC had no significant effect on the relatively high encapsulation efficiencies (>74.4%). The results of drug release studies confirmed the ability of ALG-OCH PEC to sustain drug release at pH 6.8 and 7.4. However, this PEC showed enhanced sensitivity to an acidic environment and to simulated intestinal fluid (pH 6.8) after prior exposure to an acidic medium. Additional treatment of ALG-OCH particles with EL and formation of "sandwich" ALG-OCH-EL PEC was essential not only to improve stability and decrease drug release in acidic medium, but also to achieve sustained release after the pH of dissolution medium was raised to 6.8. The obtained results suggested that ALG-OCH-EL microparticles have promising potential as pH-sensitive multiparticulate drug carriers for oral delivery of NSAIDs.
authors.affiliation: Department of Pharmaceutical Technology and Cosmetology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia. bojanc@pharmacy.bg.ac.rs
authors.forename: Bojan
authors.initials: B
authors.lastname: Calija
authors.forename: Nebojša
authors.initials: N
authors.lastname: Cekić
authors.forename: Snežana
authors.initials: S
authors.lastname: Savić
authors.forename: Rolf
authors.initials: R
authors.lastname: Daniels
authors.forename: Bojan
authors.initials: B
authors.lastname: Marković
authors.forename: Jela
authors.initials: J
authors.lastname: Milić
mesh_terms: D000284:Administration, Oral; D000464:Alginates; D002686:Chitin / Q000031:analogs & derivatives; D048271:Chitosan; D016503:Drug Delivery Systems; D004573:Electrolytes / Q000737:chemistry; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006863:Hydrogen-Ion Concentration; D009844:Oligosaccharides; D010316:Particle Size; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D011109:Polymethacrylic Acids; D013499:Surface Properties
chemical_list: D000464:Alginates; D004573:Electrolytes; D006603:Hexuronic Acids; D009844:Oligosaccharides; D011108:Polymers; D011109:Polymethacrylic Acids; C493484:oligochitosan; D002686:Chitin; C038300:methylmethacrylate-methacrylic acid copolymer; D020723:Glucuronic Acid; D048271:Chitosan