Title page for ETD etd-11192009-135706


Type of Document Dissertation
Author Wang, Hezhong
Author's Email Address wangh@vt.edu
URN etd-11192009-135706
Title Chitosan-Cellulose Nanocrystal Polyelectrolyte Complex Particles: Preparation, Characterization, and In Vitro Drug Release Properties
Degree PhD
Department Wood Science and Forest Products
Advisory Committee
Advisor Name Title
Roman, Maren Committee Chair
Davis, Richey M. Committee Member
Duncan, Susan E. Committee Member
O'Keefe, Sean F. Committee Member
Renneckar, Scott H. Committee Member
Keywords
  • drug delivery
  • polyelectrolyte complex
  • chitosan
  • cellulose nanocsrystals
  • caffeine
  • ibuprofen
Date of Defense 2009-10-22
Availability restricted
Abstract
Chitosan–Cellulose Nanocrystal Polyelectrolyte Complex Particles:Preparation, Characterization, and In Vitro Drug Release Properties

Hezhong Wang

ABSTRACT

Polyelectrolyte complexes (PECs) between chitosan, a mucoadhesive, intestinal mucosal permeability-enhancing polysaccharide, and cellulose nanocrystals, rod-like cellulose nanoparticles with sulfate groups on their surface, have potential applications in oral drug delivery. The purpose of this research was to develop an understanding of the formation and properties of chitosan–cellulose nanocrystal PECs and determine their in vitro drug release properties, using caffeine and ibuprofen as model drugs. Cellulose nanocrystals were prepared by sulfuric acid hydrolysis of bleached wood pulp. Chitosans with three different molecular weights (81, 3•103, 6•103 kDa) and four different degrees of deacetylation (77, 80, 85, 89%) were used. PEC formation was studied by turbidimetric titration. PEC particles were characterized by FT-IR spectroscopy, scanning electron microscopy, dynamic light scattering, and laser Doppler electrophoresis. The formation and properties of chitosan–cellulose nanocrystal PEC particles were governed by the strong mismatch in the densities of the ionizable groups. The particles were composed primarily of cellulose nanocrystals. Particle shape and size strongly depended on the mixing ratio and pH of the surrounding medium. The ionic strength of the surrounding medium, and the molecular weight and degree of deacetylation of chitosan had a minor effect. Release of caffeine from the chitosan–cellulose nanocrystal PEC particles was rapid and uncontrolled. Ibuprofen-loaded PEC particles showed no release in simulated gastric fluid and rapid release in simulated intestinal fluid. Further evaluation studies should focus on the expected mucoadhesive and permeability-enhancing properties of chitosan–cellulose nanocrystal PEC particles.

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