title: Long-term degradation study of hyaluronic acid in aqueous solutions without protection against microorganisms.
abstract: The degradation of hyaluronan (HA) of different molecular weights (Mw 14.3, 267.2 and 1160.6 kDa, measured for fresh solutions, before degradation) was studied in aqueous solutions by SEC-MALLS determination of molecular mass, polydispersity and conformation parameters. The solutions were stored either at laboratory or refrigerator temperatures for two months. After this period the weight average molecular weight decreased by 90% for 14.3 kDa, 95% for 267.2 kDa and 71% for 1160.6 kDa hyaluronan (room temperature) or 5.6% for 14.3 kDa, 6.2% for 267.2 kDa and 7.7% for 1160.6 kDa hyaluronan (refrigerator temperature). The hyaluronan aqueous solutions studied did not contain sodium azide or other protectants against microorganisms, because the aim of our study was to assess the degradation in solutions to be used in medicine or cosmetics (without any compounds that are poisonous or toxic for the human body). The solvent used to prepare the samples was pure water. The polydispersity of all the samples remained unaltered during the entire degradation at both temperatures. This indicates a non-random mechanism of degradation.
authors.affiliation: Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic; Institute of Chemistry Timisoara of the Romanian Academy, 24 Mihai Viteazul Bvd., Timisoara 300223, Romania. Electronic address: simulescu@fch.vutbr.cz.
authors.forename: Vasile
authors.initials: V
authors.lastname: Simulescu
authors.affiliation: Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Kalina
authors.affiliation: Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Mondek
authors.affiliation: Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
authors.forename: Miloslav
authors.initials: M
authors.lastname: Pekař
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D050260:Carbohydrate Metabolism; D006820:Hyaluronic Acid / Q000737:chemistry* / Q000378:metabolism; D064307:Microbiota / Q000187:drug effects / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D012996:Solutions; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D012996:Solutions; D014867:Water; D006820:Hyaluronic Acid
keywords: Degradation; Hyaluronic acid; MHS plot; Polymer conformation; SEC-MALLS