title: Aging phenomena of chitosan and chitosan-diclofenac sodium system detected by low-frequency dielectric spectroscopy.
abstract: The use of natural polymers for design of dosage form has received considerable attention recently, especially from the safety point of view. Among these polymers, chitosan shows very interesting biological, chemical and physical properties which makes it possible to use chitosan for various pharmaceutical applications. Microcrystalline chitosan (MCCh) is a special multifunctional polymeric material existing in the form of either of gelatinous water dispersion or a powder. Thermal aging of chitosan and chitosan-diclofenac sodium mixture have been studied using low-frequency dielectric measurements. The aging was carried out by annealing in ambient atmosphere in the temperature range between 25 degrees C and 100 degrees C. The dielectric losses in the aged samples proved to decrease by about one order of magnitude. The additional measurements of molecular weight distribution and infrared absorption were also carried out for better understanding of nature of the ageing phenomena. Partial evacuation of water, cross-linking and improvement of structural order may be suggested to be a result of thermal aging of the investigated materials.
authors.affiliation: Institute of Chemistry, Faculty of Pharmacy, Medical University, Lódź, Poland.
authors.forename: K H
authors.initials: KH
authors.lastname: Bodek
authors.forename: G W
authors.initials: GW
authors.lastname: Bak
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000737:chemistry*; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000737:chemistry*; D002686:Chitin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry; D048271:Chitosan; D004008:Diclofenac / Q000008:administration & dosage / Q000737:chemistry*; D004337:Drug Carriers; D006361:Heating; D008970:Molecular Weight; D013055:Spectrophotometry, Infrared; D013057:Spectrum Analysis / Q000379:methods; D014867:Water / Q000032:analysis
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001672:Biocompatible Materials; D004337:Drug Carriers; D014867:Water; D002686:Chitin; D004008:Diclofenac; D048271:Chitosan