title: Preparation of cross-linked chitosan microspheres by spray drying: effect of cross-linking agent on the properties of spray dried microspheres.
abstract: Chitosan microspheres cross-linked with three different cross-linking agents viz, tripolyphosphate (TPP), formaldehyde (FA) and gluteraldehyde (GA) have been prepared by spray drying technique. The influence of these cross-linking agents on the properties of spray dried chitosan microspheres was extensively investigated. The particle size and encapsulation efficiencies of thus prepared chitosan microspheres ranged mainly between 4.1-4.7 microm and 95.12-99.17%, respectively. Surface morphology, % erosion, % water uptake and drug release properties of the spray dried chitosan microspheres was remarkably influenced by the type (chemical or ionic) and extent (1 or 2% w/w) of cross-linking agents. Spray dried chitosan microspheres cross-linked with TPP exhibited higher swelling capacity, % water uptake, % erosion and drug release rate at both the cross-linking extent (1 and 2% w/w) when compared to those cross-linked with FA and GA. The sphericity and surface smoothness of the spray dried chitosan microspheres was lost when the cross-linking extent was increased from 1 to 2% w/w. Release rate of the drug from spray dried chitosan microspheres decreased when the cross-linking extent was increased from 1 to 2% w/w. The physical state of the drug in chitosan-TPP, chitosan-FA and chitosan-GA matrices was confirmed by the X-ray diffraction (XRD) study and found that the drug remains in a crystalline state even after its encapsulation. Release of the drug from chitosan-TPP, chitosan-FA and chitosan-GA matrices followed Fick's law of diffusion.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Sungbuk-ku, Seoul, South Korea.
authors.forename: K G H
authors.initials: KG
authors.lastname: Desai
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations; D003890:Desiccation; D004337:Drug Carriers / Q000737:chemistry*; D005557:Formaldehyde / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011122:Polyphosphates / Q000737:chemistry
chemical_list: D018712:Analgesics, Non-Narcotic; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D011122:Polyphosphates; D005557:Formaldehyde; D000082:Acetaminophen; D048271:Chitosan; C005692:triphosphoric acid; D005976:Glutaral