title: Tannic acid incorporation in chitosan-based microparticles and in vitro controlled release.
abstract: Chitosan, a natural polycationic polysaccharide, was coupled with two polyanionic polymers: Na-alginate and carboxymethylcellulose (CMC) and with tannic acid (TA) obtaining three species of self-assembled complexes: chitosan/alginate/TA (sample 1), chitosan/TA (sample 2) and chitosan/CMC/TA (sample 3). The microparticle formation was achieved by dropwise addition of one solution into other by using a coaxial airflow sprayer. These systems were characterized with regard to particle size distribution, thermal stability, tannic acid entrapment efficiency. Sample 2 showed quite a different behavior compared to the other two samples; the particle diameter is located in the nanometric region, the quantity of incorporated tannic acid is higher than in the other two samples and the material shows better thermal stability. The release of tannic acid from these complexes was studied in water (pH = 5.89), phosphates buffer (pH = 7.04) and acetate buffer (pH = 4.11). These studies revealed two distinct periods in tannic acid delivery process: an initial period, varying between 4 and 10 h, characterized by a high release rate with a delivered tannic acid amount of approximately 80% of the incorporated polyphenol and a second period, which starts after 20 to 30 h of delivery and it ends after approximately 120 h, when the release process takes place with low and constant rate and the kinetic curve is linear--characteristic for a zero order kinetic.
authors.affiliation: Chemical Engineering Department, Chemical Engineering and Environment Protection Faculty, Technical University of Iasi, Iasi, Romania. naelenei@ch.tuiasi.ro
authors.forename: Neculai
authors.initials: N
authors.lastname: Aelenei
authors.forename: Marcel Ionel
authors.initials: MI
authors.lastname: Popa
authors.forename: Ovidiu
authors.initials: O
authors.lastname: Novac
authors.forename: Gabriela
authors.initials: G
authors.lastname: Lisa
authors.forename: Lacramioara
authors.initials: L
authors.lastname: Balaita
mesh_terms: D000464:Alginates / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008422:Materials Testing; D008863:Microspheres; D010316:Particle Size; D017550:Spectroscopy, Fourier Transform Infrared; D013634:Tannins / Q000008:administration & dosage*; D013818:Thermogravimetry
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D006603:Hexuronic Acids; D013634:Tannins; D020723:Glucuronic Acid; D048271:Chitosan