title: Chitosan derivatives alter release profiles of model compounds from calcium phosphate implants.
abstract: The aim of the current study was to evaluate the impact of chitosan derivatives, namely N-octyl-chitosan and N-octyl-O-sulfate chitosan, incorporated in calcium phosphate implants to the release profiles of model drugs. The rate and extent of calcein (on M.W. 650 Da) ED, and FITC-dextran (M.W. 40 kDa) on in vitro release were monitored by fluorescence spectroscopy. Results show that calcein release is affected by the type of chitosan derivative used. A higher percentage of model drug was released when the hydrophilic polymer N-octyl-sulfated chitosan was present in the tablets compared with the tablets containing the hydrophobic polymer N-octyl-chitosan. The release profiles of calcein or FD from tablets containing N-octyl-O-sulfate revealed a complete release for FD after 120 h compared with calcein where 20% of the drug was released over the same time period. These results suggest that the difference in the release profiles observed from the implants is dependent on the molecular weight of the model drugs. These data indicate the potential of chitosan derivatives in controlling the release profile of active compounds from calcium phosphate implants.
authors.affiliation: School of Pharmacy and Biomedical Sciences, University of Portsmouth, St. Michael's Building, White Swan Road, Portsmouth PO1 2DT, UK.
authors.forename: S
authors.initials: S
authors.lastname: Green
authors.forename: M
authors.initials: M
authors.lastname: Roldo
authors.forename: D
authors.initials: D
authors.lastname: Douroumis
authors.forename: N
authors.initials: N
authors.lastname: Bouropoulos
authors.forename: D
authors.initials: D
authors.lastname: Lamprou
authors.forename: D G
authors.initials: DG
authors.lastname: Fatouros
mesh_terms: D002130:Calcium Phosphates / Q000737:chemistry; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000737:chemistry; D005452:Fluoresceins / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D015394:Molecular Structure; D019736:Prostheses and Implants; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002130:Calcium Phosphates; D003911:Dextrans; D005452:Fluoresceins; C528556:N-octyl-O-sulfate chitosan; C015219:fluorescein isothiocyanate dextran; D048271:Chitosan; D017886:Durapatite; C020243:calcium phosphate; D016650:Fluorescein-5-isothiocyanate; C007740:fluorexon