title: In vivo biocompatibility and degradability of a novel injectable-chitosan-based implant.
abstract: A novel injectable-chitosan-based delivery system with low cytotoxicity was fabricated in the study. The chitosan microspheres with small particle size, low crystallinity and good sphericity were prepared by a spray-drying method followed by treating with a crosslinker. In the study, a naturally occurring crosslinking reagent (genipin), which has been used in herbal medicine and in the production of food dyes, was used to crosslink the chitosan microspheres. The glutaraldehyde-crosslinked counterparts were used as a control. Histological study of the genipin-crosslinked chitosan microspheres injected intramuscularly into the skeletal muscle of a rat model showed a less inflammatory reaction than its glutaraldehyde-crosslinked counterparts. The results of the scanning electron microscopic examination indicated that the glutaraldehyde-crosslinked chitosan microspheres retrieved at 12-week postoperatively were already degraded into a loose and porous structure. However, the degradation of the genipin-crosslinked chitosan microspheres was not significant after 20 weeks of implantation. The results of the study demonstrated that the genipin-crosslinked chitosan microspheres have a superior biocompatibility and a slower degradation rate than the glutaraldehyde-crosslinked chitosan microspheres. Accordingly, the genipin-crosslinked chitosan microspheres may be a suitable polymeric carrier for long-acting injectable drug delivery.
authors.affiliation: Department of Mathematics, Physics and Chemistry, Chinese Naval Academy, Kaohsiung, Taiwan, ROC.
authors.forename: Fwu-Long
authors.initials: FL
authors.lastname: Mi
authors.forename: Yu-Chiun
authors.initials: YC
authors.lastname: Tan
authors.forename: Hsiang-Fa
authors.initials: HF
authors.lastname: Liang
authors.forename: Hsing-Wen
authors.initials: HW
authors.lastname: Sung
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D002240:Carbohydrate Sequence; D002686:Chitin / Q000008:administration & dosage* / Q000031:analogs & derivatives; D048271:Chitosan; D004343:Drug Implants; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D051381:Rats; D017208:Rats, Wistar; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D004343:Drug Implants; D002686:Chitin; D048271:Chitosan