title: Effects of steam sterilization on thermogelling chitosan-based gels.
abstract: A new thermogelling chitosan-glycerophosphate system has been recently proposed for biomedical applications such as drug and cell delivery. The objectives of this work were to characterize the effect of steam sterilization on the in vitro and in vivo end performances of the gel and to develop a filtration-based method to assess its sterility. Autoclaving 2% (w/v) chitosan solutions for as short as 10 min resulted in a 30% decrease in molecular weight, 3-5-fold decrease in dynamic viscosity, and substantial loss of mechanical properties of the resulting gel. However, sterilization did not impair the ability of the system to form a gel at 37 degrees C. The antimicrobial activity of chitosan against several microorganisms was evaluated after inoculation of chitosan solutions and removal of the cells by filtration. It was found that, although chitosan was bacteriostatic against the heat sterilization bioindicator Bacillus stearothermophilus, the bacteria could rapidly grow after separation from the chitosan solution by filtration. This indicated that B. stearothermophilus is an adequate strain to validate a heat sterilization method on chitosan preparations, and accordingly this strain was used to assess the sterility of chitosan solution following a 10 min autoclaving time.
authors.affiliation: Faculty of Pharmacy, University of Montreal, C.P. 6128 succ. centre-ville, Montreal, Qc, H3C 3J7, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Jarry
authors.forename: C
authors.initials: C
authors.lastname: Chaput
authors.forename: A
authors.initials: A
authors.lastname: Chenite
authors.forename: M A
authors.initials: MA
authors.lastname: Renaud
authors.forename: M
authors.initials: M
authors.lastname: Buschmann
authors.forename: J C
authors.initials: JC
authors.lastname: Leroux
mesh_terms: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D002176:Candida albicans / Q000187:drug effects; D002686:Chitin / Q000031:analogs & derivatives / Q000737:chemistry*; D048271:Chitosan; D002850:Chromatography, Gel; D004548:Elasticity; D004926:Escherichia coli / Q000187:drug effects; D005374:Filtration; D005782:Gels; D001411:Geobacillus stearothermophilus / Q000187:drug effects; D006358:Hot Temperature; D008422:Materials Testing; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight; D012996:Solutions; D013211:Staphylococcus aureus / Q000187:drug effects; D013242:Sterilization / Q000379:methods*; D013314:Stress, Mechanical; D013997:Time Factors; D014783:Viscosity; D014867:Water; D016474:Weight-Bearing
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D001672:Biocompatible Materials; D005782:Gels; D012996:Solutions; D014867:Water; D002686:Chitin; D048271:Chitosan